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Full-Text Articles in Physical Sciences and Mathematics

Magnetic Properties And Magnetocaloric Effect Of Ndmn2−Xtixsi2 Compounds, M F. Md Din, Jianli Wang, S J. Campbell, R Zeng, W D. Hutchison, M Avdeev, S J. Kennedy, S X. Dou Oct 2013

Magnetic Properties And Magnetocaloric Effect Of Ndmn2−Xtixsi2 Compounds, M F. Md Din, Jianli Wang, S J. Campbell, R Zeng, W D. Hutchison, M Avdeev, S J. Kennedy, S X. Dou

Australian Institute for Innovative Materials - Papers

The structural and magnetic properties of the intermetallic compounds NdMn2−xTixSi2(x = 0, 0.1, 0.2, and 0.3) have been studied by x-ray and high resolution neutron powder diffraction, specific heat, dc magnetization, and differential scanning calorimetry measurements over the temperature range 3–450 K. The Curie temperature and Néel temperature of NdMn2Si2 decrease from TC = 36 K and TN = 380 K to TC = 14 K and TN = 360 K, respectively, on substitution of Ti (x = 0.3) for Mn. The magnetocaloric effect …


Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou Oct 2013

Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou

Josip Horvat

"VNx nanoparticles and nanowires have been prepared by nitrifying V2O5 nanoparticles (NP) and nanowires (NW). The V2O5 NP and NW were synthesized by a facile hydrothermal method. Magnetic susceptibility (chi) and magnetization measurements showed long range superconducting ordering (LRSO) at the temperature of 5.8 K for NW, but there was no observation of LRSO (at least down to 2 K) for the NP sample, which is a much lower temperature than for the corresponding bulk, while both NP and NW showed the absence of long range magnetic ordering, at least down to 2 K. However, the chi data showed that …


Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou Jul 2013

Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou

Jianli Wang

We have carried out a detailed investigation of the magnetic phase transition in MnFeP0.5As0.4Si0.1. Temperature hysteresis has been observed in the variable temperature magnetization curves (Bappl = 0.01 T) with TC W ~ 302 K on warming and TC C ~ 292 K on cooling. The first order nature of this transition in MnFeP0.5As0.4Si0.1 is confirmed by the negative slope obtained from isotherms of M2 versus B/M around the critical temperature. Linear thermal expansion measurements reveal a large volume change, ΔV/V∼8.7×10-3, at the magnetic phase transition and that this magnetovolume effect is suppressed to ΔV/V ∼ 5.5×10-3 in an applied …


Magnetic Properties Of Ho2fe17-Xmnx - Influence Of Mn Substitution, Jianli Wang, Stewart J. Campbell, A J Studer, S J. Kennedy, Rong Zeng Jul 2013

Magnetic Properties Of Ho2fe17-Xmnx - Influence Of Mn Substitution, Jianli Wang, Stewart J. Campbell, A J Studer, S J. Kennedy, Rong Zeng

Jianli Wang

The structural and magnetic properties of Ho2Fe17−xMnx (x=0-5) have been investigated by x-ray diffraction, Mössbauer spectroscopy and DC magnetization measurements (0-5 T) over the temperature range 4.5-350 K. Similar to other ferrimagnetic R2Fe17-xMnx systems, the unit cell volume generally increases with Mn content other than for low Mn values where a slight maximum is detected around x ∼ 0.5. The nature of the magnetic phase transitions around TC is shown by Arrot plot analysis to be second order for all samples. The Curie temperature remains essentially unchanged …


Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou Jul 2013

Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou

Jianli Wang

The critical behaviour of Mn0.94Nb0.06CoGe alloy around the paramagnetic-ferromagnetic phase transition was studied based on the field dependence on magnetic entropy change. By using the obtained exponents, the modified Arrott plot is consistent with that by using conventional method. These critical exponents are confirmed by the Widom scaling relation. Based on these critical exponents, the magnetization, field and temperature data around Tc collapse into two curves obeying the single scaling equation MðH; e)¼ebf6(H/ebþc). The calculated critical exponents not only obey the scaling theory but also anastomose the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, …


Magnetic Properties Of Bi2femno6: A Multiferroic Material With Double-Perovskite Structure, Yi Du, Zhenxiang Cheng, S X. Dou, Xiaolin Wang, Hua Zhao, Hideo Kimura Jun 2013

Magnetic Properties Of Bi2femno6: A Multiferroic Material With Double-Perovskite Structure, Yi Du, Zhenxiang Cheng, S X. Dou, Xiaolin Wang, Hua Zhao, Hideo Kimura

Shi Xue Dou

Single phase Bi2FeMnO6 was synthesized on Si substrates by an electrospray method. Three peaks were observed in the temperature dependence of magnetization curve, which is attributed to the inhomogeneous distribution of Fe3+ and Mn3+. The observed magnetic peaks at 150 K, 260 K, and 440 K correspond to orderings of the ferrimagnetic Fe–O–Mn, and antiferromagnetic Mn–O–Mn and Fe–O–Fe, respectively. Heat capacity measurements were carried out to confirm these magnetic transitions. The Debye temperature of Bi2FeMnO6 is 339 K, calculated from Debye–Einstein fitting.


Lanthanum Doped Multiferroic Dyfeo3: Structural And Magnetic Properties, Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou Jun 2013

Lanthanum Doped Multiferroic Dyfeo3: Structural And Magnetic Properties, Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou

Shi Xue Dou

Lanthanum doped multiferroic DyFeO3 was synthesized by solid state reaction. X-ray diffraction and refinement show that the lattice parameters of Dy1−xLaxFeO3 increase linearly with the La content. Raman spectroscopy reveals that the short-range force constant in Dy1−xLaxFeO3 is decreased by La3+ ion substitution. The spin reorientation phase transition temperature (TSRPT) is observed to decrease along with the doping level. The antiferromagnetic ordering temperature TN of Fe3+ ions is depressed with increasing doping level. Both decreasing TSRPT and decreasing TN indicate that Fe–Dy and Fe–Fe interactions are weakened by La substitution. It is found that the electron configuration of Fe3+ is …


Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou Jun 2013

Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou

Shi Xue Dou

The critical behaviour of Mn0.94Nb0.06CoGe alloy around the paramagnetic-ferromagnetic phase transition was studied based on the field dependence on magnetic entropy change. By using the obtained exponents, the modified Arrott plot is consistent with that by using conventional method. These critical exponents are confirmed by the Widom scaling relation. Based on these critical exponents, the magnetization, field and temperature data around Tc collapse into two curves obeying the single scaling equation MðH; e)¼ebf6(H/ebþc). The calculated critical exponents not only obey the scaling theory but also anastomose the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, …


Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou Jun 2013

Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou

Shi Xue Dou

"VNx nanoparticles and nanowires have been prepared by nitrifying V2O5 nanoparticles (NP) and nanowires (NW). The V2O5 NP and NW were synthesized by a facile hydrothermal method. Magnetic susceptibility (chi) and magnetization measurements showed long range superconducting ordering (LRSO) at the temperature of 5.8 K for NW, but there was no observation of LRSO (at least down to 2 K) for the NP sample, which is a much lower temperature than for the corresponding bulk, while both NP and NW showed the absence of long range magnetic ordering, at least down to 2 K. However, the chi data showed that …


Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou Jun 2013

Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou

Shi Xue Dou

We have carried out a detailed investigation of the magnetic phase transition in MnFeP0.5As0.4Si0.1. Temperature hysteresis has been observed in the variable temperature magnetization curves (Bappl = 0.01 T) with TC W ~ 302 K on warming and TC C ~ 292 K on cooling. The first order nature of this transition in MnFeP0.5As0.4Si0.1 is confirmed by the negative slope obtained from isotherms of M2 versus B/M around the critical temperature. Linear thermal expansion measurements reveal a large volume change, ΔV/V∼8.7×10-3, at the magnetic phase transition and that this magnetovolume effect is suppressed to ΔV/V ∼ 5.5×10-3 in an applied …


Single-Crystal Growth And Anisotropic Magnetic Properties Of Nonstoichiometric Three-Layer Sodium Cobalt Oxides, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou Jun 2013

Single-Crystal Growth And Anisotropic Magnetic Properties Of Nonstoichiometric Three-Layer Sodium Cobalt Oxides, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou

Shi Xue Dou

Large single crystals of α-NaxCoO2 (x=0.91, 0.92, and 0.93) have been successfully fabricated by using the traveling solvent floating zone method. Details on the crystal growth are discussed. The crystal structures were characterized using powder x-ray diffraction and Rietveld refinement. The magnetic susceptibility measurements show that the magnetic properties depend strongly on x. The compound was found to be antiferromagnetic at TN ≈ 20 K for x=0.91 and x=0.92, and paramagnetic for x=0.93. The in-plane and out-of-plane anisotropies were observed for the x=0.91 crystals. In addition, the derived anisotropic g-factor ratios (gab /gc) from the anisotropic susceptibility along H||ab and …


A Sign Of Field-Induced First Order Magnetic State Transition And Giant Reversible Magnetocaloric Effect In Cobalt Hydroxide Nanosheets, Precious Shamba, Rong Zeng, J Q Wang, S X. Dou Jun 2013

A Sign Of Field-Induced First Order Magnetic State Transition And Giant Reversible Magnetocaloric Effect In Cobalt Hydroxide Nanosheets, Precious Shamba, Rong Zeng, J Q Wang, S X. Dou

Shi Xue Dou

We report the synthesis of β−Co(OH)2 nanosheets using microwave assisted hydrothermal and conventional chemical reaction methods. A magnetic transition at an onset temperature, T1 ~ 96 K, and a sign of antiferromagnetic state transition at the Néel temperature, TN=9~10 K, can be determined from M-T curves and M-H curves magnetic properties investigation. It is found that a sign of field-induced first order transition below 9 K, act as a role of reversing the magnetocaloric effect from negative to positive value. The large reversible magnetic-entropy change (∆SM) of 17 J/kg K around 11 K for a field change of 5 T …


Structure, Ferroelectric Properties, And Magnetic Properties Of The La-Doped Bismuth Ferrite, Zhenxiang Cheng, Aihua Li, Xiaolin Wang, S X. Dou, Kiyoshi Ozawa, Hideo Kimura, S Zhang, Thomas R. Shrout Jun 2013

Structure, Ferroelectric Properties, And Magnetic Properties Of The La-Doped Bismuth Ferrite, Zhenxiang Cheng, Aihua Li, Xiaolin Wang, S X. Dou, Kiyoshi Ozawa, Hideo Kimura, S Zhang, Thomas R. Shrout

Shi Xue Dou

Bi1-xLaxFeO3 ceramics with x=0, 0.1, 0.2, and 0.3 have been synthesized by solid state reaction, starting from metal oxides. A series of structure transformations is found to depend upon the doping level. Below 10% La doping, Bi1-xLaxFeO3 maintains the rhombohedral structure of BiFeO3. However, for Bi0.8La0.2FeO3 and Bi0.7La0.3FeO3, the structures change to the orthorhombic and tetragonal, respectively. La doping significantly reduces electric leakage and leads to successful observation of electrical polarization hysteresis loops. Doping with La also enhances the ferromagnetic moment, due to the broken cycloid spin structure caused by the changes in the crystalline structure.


Structure, Magnetic, And Thermal Properties Of Nd1-Xlaxcro3 (0 ≤ X ≤ 1.0), Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou Jun 2013

Structure, Magnetic, And Thermal Properties Of Nd1-Xlaxcro3 (0 ≤ X ≤ 1.0), Yi Du, Zhenxiang Cheng, Xiaolin Wang, S X. Dou

Shi Xue Dou

Perovskite-type Nd1−xLaxCrO3(0 ≤ x ≤1.0) polycrystalline samples were synthesized using solid state reaction. Structural studies indicate that the lattice parameters, metal–oxygen bond lengths, and angles of Nd1−xLaxCrO3 strongly depend on the La content. Two magnetic transition temperatures, Cr3+ antiferromagnetic ordering temperature (TN) and the spin reorientation phase transition temperature (TSRPT), have been observed in the M-T curves. The increase in TN and decrease in TSRPT with increasing x value can be explained by the change in the magnetic interactions due to La doping. The heat capacity of Nd1−xLaxCrO3 measured from 2 to 300 K reveals that the lattice, electronic, and …


Giant Magnetic Entropy Change In Colossal Magnetoresistance In La0.7ca0.3mno3 Material In Low Field, Jyotish Debnath, Rong Zeng, Jung Ho Kim, S X. Dou Jun 2013

Giant Magnetic Entropy Change In Colossal Magnetoresistance In La0.7ca0.3mno3 Material In Low Field, Jyotish Debnath, Rong Zeng, Jung Ho Kim, S X. Dou

Shi Xue Dou

The structural, magnetic, and magnetocaloric properties of the manganite La0.7Ca0.3MnO3 have been studied. Change in the giant magnetic entropy was observed without any noticeable magnetic hysteresis but with small thermal hysteresis losses. We observed a first order magnetic phase transition around 251 K. The magnetic entropy change observed in this work is estimated to be 5.27 J/kg K for field changes from 0 to 1.5 T based on magnetization measurements. This value is about twice as large as those for other perovskite manganites and is even larger than for Gd-based magnetic materials at low fields. In addition, the entropy change …


Kinetic Roughening Of Magnetic Flux Penetration In Mgb2 Thin Films, Andrea Lucarelli, Stephanie Hummert, Andrea Chaney, Gunter Lupke, Brian Moeckly, Yue Zhao, S X. Dou Jun 2013

Kinetic Roughening Of Magnetic Flux Penetration In Mgb2 Thin Films, Andrea Lucarelli, Stephanie Hummert, Andrea Chaney, Gunter Lupke, Brian Moeckly, Yue Zhao, S X. Dou

Shi Xue Dou

Time-resolved magneto-optical studies are performed on MgB2 thin film samples grown by in situ pulsed laser deposition and in situ reactive deposition technique. The latter reveal dendritic avalanche-free flux penetration. The kinetic roughening of magnetic flux penetration is studied for applied ac current. Dynamic scaling laws determined for both static field and ac current are consistent with the directed percolation depinning model, placing the vortex dynamics in MgB2 in the same universality class as YBCO and Nb.


Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng Jun 2013

Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng

Shi Xue Dou

The authors present their studies on the band structures and on the magnetic and magnetotransport properties of the high pressure phase of Sr2-xRExCoO4 [rare earth (RE)=Gd and Y, x=0.1-0.5] compounds which were synthesized by a high pressure and high temperature technique. The authors found that as x increases, the magnetoresistance {(PH-P0)/p0} increases up to -17% at 5 K and 7 T, which is 2.5 times higher than that for undoped Sr2CoO4, although the ferromagnetic transition drops from 255 to 200 K for the Gd doping with x=0.3. The saturation moments at low temperature are significantly enhanced for the Gd doped …


Magnetic And Transport Properties Of Transition Metal Doped Polycrystalline In2o3, Germanas Peleckis, Xiaolin Wang, S X. Dou Jun 2013

Magnetic And Transport Properties Of Transition Metal Doped Polycrystalline In2o3, Germanas Peleckis, Xiaolin Wang, S X. Dou

Shi Xue Dou

Synthesis and characterization of transition metal (TM)-doped In 2O3 oxide is reported. Most of the samples were found to be paramagnetic, and only Ye and Cr co-doped sample showed as light trace of ferromagnetism at 300 K with saturation magnetization M s = 0.35 emug/g. Measured transport properties revealed significant differences in transport among the samples. The absolute value of electrical resistivity for the In1.8Fe0.1Mn0.1O3 sample at 300 K was rho= 9.4 x 103 Omega middot cm, while In1.8Fe0.1Cr0.1O3 had rho = 62 Omega middot cm at the same temperature. Furthermore, magnetoresistance (MR) studies of In1.8Fe0.1Cr0.1O3 showed that the sign …


Josephson-Vortex Flow Resistance In Bi2sr2ca2cu3oy Single Crystals And Its Possible Application In The Manipulation Of Spin And Charge Textures In Diluted Magnetic Semiconductors, Xiaolin Wang, C T Lin, B Liang, S Yu, S Ooi, K Hirata, S Y Ding, Dongqi Shi, S X. Dou, Zhi W. Lin, Jian G. Zhu Jun 2013

Josephson-Vortex Flow Resistance In Bi2sr2ca2cu3oy Single Crystals And Its Possible Application In The Manipulation Of Spin And Charge Textures In Diluted Magnetic Semiconductors, Xiaolin Wang, C T Lin, B Liang, S Yu, S Ooi, K Hirata, S Y Ding, Dongqi Shi, S X. Dou, Zhi W. Lin, Jian G. Zhu

Shi Xue Dou

In this work, the flow of the Josephson vortices (JVs) has been studied for the highly anisotropic Bi2Sr2Ca2Cu3Oy (Bi2223) single crystals. A giant flow of JVs or giant positive magnetoresistance (MR) of over 500%-2000% was obtained in fields of 0.1-5 T and remained almost constant over a wide temperature range from 110 down to 4 K, in contrast to superconducting vortices (SVs), which only produced MR in the vicinity of Tc. The flow of the JVs is expected to be much faster than that of SVs. It is proposed that the Josephson vortices could be used to manipulate the spin …


Magnetic Anisotropy Of Naxcoo2 Single Crystals, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou Jun 2013

Magnetic Anisotropy Of Naxcoo2 Single Crystals, Dapeng Chen, Xiaolin Wang, C T Lin, S X. Dou

Shi Xue Dou

We report the magnetic properties of single crystals of NaxCoO2 (x=0.42, 0.82, and 0.87). The magnetic susceptibility measurements revealed considerable anisotropy along H parallel to ab and H parallel to c for the as-grown single crystals. It was found that an antiferromagnetic transition with a Neel temperature T-N=21 K occurred for the x=0.82 sample, and there was a paramagnetic phase for the x=0.87 sample over a wide temperature range from 2 to 300 K, but the sample with x=0.42 shows a monotonic increase of chi with increasing temperature above similar to 100 K. In addition, the x=0.82 sample has the …


Colloidal Nano-Apatite Particles With Active Luminescent And Magentic Properties For Biotechnology Applications, Rajendra Kasinath, Kumar Ganesan Jan 2013

Colloidal Nano-Apatite Particles With Active Luminescent And Magentic Properties For Biotechnology Applications, Rajendra Kasinath, Kumar Ganesan

Environmental Engineering

Colloidal Nano-apatite Particles with Active Luminescent and Magentic Properties for Biotechnology Applications. The synthesis of functional nano-materials is a burgeoning field that has produced remarkable and consistent breakthroughs over the last two decades. Individual particles have become smaller and shown potential for well defined functionality. However, there are still unresolved problems, a primary one being the loss of functionality and novelty due to uncontrolled aggregation driven by surface energy considerations. As such the first design criteria to harness the true potential of nanoparticles is to prevent unwanted agglomeration by: (1) improving, and, if possible, (2) controlling aggregation behavior. This requires …


Magnetic Phase Diagram And Correlation Between Metamagnetism And Superconductivity In Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Shane J. Kennedy, Alexey V. Pan, S X. Dou Jan 2013

Magnetic Phase Diagram And Correlation Between Metamagnetism And Superconductivity In Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Shane J. Kennedy, Alexey V. Pan, S X. Dou

Australian Institute for Innovative Materials - Papers

The magnetic superconductor Ru0.9Sr2YCu2.1O7.9 (Ru-1212Y) has been investigated using neutron diffraction under variable temperature and magnetic field. With the complementary information from magnetization measurements, we propose a magnetic phase diagram T-H for the Ru-1212 system. Uniaxial antiferromagnetic (AFM) order of 1.2μ B/Ru atoms with moments parallel to the c-axis is found below the magnetic transition temperature at ~140 K in the absence of magnetic field. In addition, ferromagnetism (FM) in the ab-plane develops below ~120 K, but is suppressed at lower temperature by superconducting correlations. Externally applied …


Critical Phenomena And Estimation Of The Spontaneous Magnetization By A Magnetic Entropy Analysis In Mn0.96nb0.04coge Alloy, Jyotish C. Debnath, A M. Strydom, P Shamba, Jianli Wang, S X. Dou Jan 2013

Critical Phenomena And Estimation Of The Spontaneous Magnetization By A Magnetic Entropy Analysis In Mn0.96nb0.04coge Alloy, Jyotish C. Debnath, A M. Strydom, P Shamba, Jianli Wang, S X. Dou

Australian Institute for Innovative Materials - Papers

Magnetic and magnetocaloric properties of the alloy Mn0.96Nb0.04CoGe have been investigated.


Thermo-Magnetic Stability Of Superconducting Films Controlled By Nano-Morphology, V V. Yurchenko, K Ilin, J M. Meckbach, M Siegel, A J. Qviller, Y M. Galperin, Tom H. Johansen Jan 2013

Thermo-Magnetic Stability Of Superconducting Films Controlled By Nano-Morphology, V V. Yurchenko, K Ilin, J M. Meckbach, M Siegel, A J. Qviller, Y M. Galperin, Tom H. Johansen

Australian Institute for Innovative Materials - Papers

Appearance of dendritic magnetic flux avalanches in superconducting films, which are associated with thermo-magnetic instability (TMI), very often indicates serious limitations for the ultimate performance of superconducting devices made of type-II superconducting thin films. We demonstrate that the stability can be controlled by a thorough adjustment of samples morphology at nano-scale, which affects internal material parameters. By this, the metal coating, commonly used as for stabilization, becomes redundant. Most importantly, we directly show by the mean of magneto-optical imaging that introduction of nano-scaled disorder dramatically changes the mode of magnetic flux propagation in the superconductors, from uniform motion of individual …


Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou Jan 2013

Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou

Australian Institute for Innovative Materials - Papers

Amorphous magnetic Ni-Co-B nanoparticles with an average size of 5 nm were added to precursor powders of MgB2 superconductor. The preparation procedure for MgB2 pellets was optimized for obtaining the best critical current density (Jc) at elevated magnetic fields. Addition of Ni-Co-B decreases the Jc for heat treatment of precursor powders at 650 ° C. Heat treatments at 770 ° C and higher improve Jc at 20 and 5 K. This improvement occurs at both temperatures through the increase of the effective connectivity between MgB2 crystals. Vortex pinning was enhanced at 5 K, but not at 20 K. Ni-Co-B nanoparticles …


Magnetic Field Induced Discontinuous Spin Reorientation In Erfeo3 Single Crystal, Hui Shen, Zhenxiang Cheng, Fang Hong, Jiayue Xu, Shujuan Yuan, Shixun Cao, Xiaolin Wang Jan 2013

Magnetic Field Induced Discontinuous Spin Reorientation In Erfeo3 Single Crystal, Hui Shen, Zhenxiang Cheng, Fang Hong, Jiayue Xu, Shujuan Yuan, Shixun Cao, Xiaolin Wang

Australian Institute for Innovative Materials - Papers

The spin reorientation of ErFeO3 that spontaneously occurs at low temperature has been previously determined to be a process involving the continuous rotation of Fe3þ spins. In this work, the dynamic process of spin reorientation in ErFeO3 single crystal has been investigated by AC susceptibility measurements at various frequencies and static magnetic fields. Interestingly, two completely discontinuous steps are induced by a relatively large static magnetic field due to the variation in the magnetic anisotropy during this process. It provides deeper insights into the intriguing magnetic exchange interactions which dominate the sophisticated magnetic phase transitions in the orthoferrite systems.


Exact Asymptotic Behavior Of Magnetic Stripe Domain Arrays, Tom H. Johansen, Alexey V. Pan, Yuri M. Galperin Jan 2013

Exact Asymptotic Behavior Of Magnetic Stripe Domain Arrays, Tom H. Johansen, Alexey V. Pan, Yuri M. Galperin

Australian Institute for Innovative Materials - Papers

The classical problem of magnetic stripe domain behavior in films and plates with uniaxial magnetic anisotropy is addressed. Exact analytical results are derived for the stripe domain widths as a function of applied perpendicular field H, in the regime where the domain period becomes large. The stripe period diverges as (H-c - H)(-1/2), where H-c is the critical (infinite period) field, an exact result confirming a previous conjecture. The magnetization approaches saturation as (H-c - H)(1/2), a behavior that compares excellently with experimental data obtained for a 4-mu m thick ferrite garnet film. The exact analytical solution provides a new …


Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou Jan 2013

Investigation Of The Critical Behavior In Mn0.94nb 0.06coge Alloy By Using The Field Dependence Of Magnetic Entropy Change, J C. Debnath, P Shamba, A M. Strydom, Jianli Wang, S X. Dou

Australian Institute for Innovative Materials - Papers

The critical behaviour of Mn0.94Nb0.06CoGe alloy around the paramagnetic-ferromagnetic phase transition was studied based on the field dependence on magnetic entropy change. By using the obtained exponents, the modified Arrott plot is consistent with that by using conventional method. These critical exponents are confirmed by the Widom scaling relation. Based on these critical exponents, the magnetization, field and temperature data around Tc collapse into two curves obeying the single scaling equation MðH; e)¼ebf6(H/ebþc). The calculated critical exponents not only obey the scaling theory but also anastomose the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, …


Band Structure, Magnetic, And Transport Properties Of Two Dimensional Compounds Sr2-Xgdxcoo4, Q W Yao, Xiaolin Wang, H Kimura, S X. Dou, Konstantin Konstantinov, Z X. Cheng, F Hong, H Zhao, H Qiu, Kiyoshi Ozawa Jan 2013

Band Structure, Magnetic, And Transport Properties Of Two Dimensional Compounds Sr2-Xgdxcoo4, Q W Yao, Xiaolin Wang, H Kimura, S X. Dou, Konstantin Konstantinov, Z X. Cheng, F Hong, H Zhao, H Qiu, Kiyoshi Ozawa

Australian Institute for Innovative Materials - Papers

The layered perovskite compound Sr2-xGdxCoO 4 has not yet been subjected to detailed study so far. In this report, structures, transport, magnetic properties, and first principle calculations will be reported for the two dimensional compounds Sr 2-xGdxCoO4 (x 0.5, 0.75, 1, 1.25). Rietveld refinement revealed that these compounds are crystallized in K2NiF 4-type structures with space group I4/mmm. It was found that the lattice parameter c decreases as x increases. Through the Curies Weiss fitting of the temperature dependent magnetization, it was found that the Sr 1.25Gd0.75CoO4 sample exhibits a weak ferromagnetic to paramagnetic transition at about 62 K, with …


Highly Water-Soluble Magnetic Iron Oxide (Fe3o4) Nanoparticles For Drug Delivery: Enhanced In Vitro Therapeutic Efficacy Of Doxorubicin And Mion Conjugates, Muhammad Irfan Majeed, Qunwei Lu, Wei Yan, Zhen Li, Irshad Hussain, Muhammad Nawaz Tahir, Wolfgang Tremel, Bien Tan Jan 2013

Highly Water-Soluble Magnetic Iron Oxide (Fe3o4) Nanoparticles For Drug Delivery: Enhanced In Vitro Therapeutic Efficacy Of Doxorubicin And Mion Conjugates, Muhammad Irfan Majeed, Qunwei Lu, Wei Yan, Zhen Li, Irshad Hussain, Muhammad Nawaz Tahir, Wolfgang Tremel, Bien Tan

Australian Institute for Innovative Materials - Papers

We report a simple one step protocol for the preparation of fairly monodisperse and highly water-soluble magnetic iron oxide nanoparticles (MIONs) through a co-precipitation method using a novel multifunctional, biocompatible and water-soluble polymer ligand dodecanethiol-polymethacrylic acid (DDT-PMAA). DDT-PMAA owing to its several intrinsic properties, not only efficiently controls the size of the MIONs but also gives them excellent water solubility, long time stability against aggregation and oxidation, biocompatibility and multifunctional surface rich in thioether and carboxylic acid groups. The molecular weight and concentration of the polymer ligand were optimized to produce ultrasmall (4.6 +/- 0.7 nm) MIONs with high magnetization …