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Full-Text Articles in Physics
Effect Of Random Anisotropy On Magnetic Properties Of Amorphous Systems, J.D. Patterson, G.R. Gruzalski, David J. Sellmyer
Effect Of Random Anisotropy On Magnetic Properties Of Amorphous Systems, J.D. Patterson, G.R. Gruzalski, David J. Sellmyer
David Sellmyer Publications
We consider the random anisotropy model for amorphous magnetism by making a local-mean-field approximation (LMFA) on arrays of spin-one particles. Hysteresis loops and the temperature (T) dependence of several thermodynamic quantities are presented for various values of the ratio of the strength of the exchange (J) to the strength of the uniaxial anisotropy (D). Using the LMFA limits us to systems with a small number (N) of spins, of which we explicitly consider N=64, 216, and 1000. We assume periodic boundary conditions on a system with N1/3 spins along …
Magnetic Ordering And Local Random Anisotropy In Dilute Magnetic Glasses, G.R. Gruzalski, J.D. Patterson, David J. Sellmyer
Magnetic Ordering And Local Random Anisotropy In Dilute Magnetic Glasses, G.R. Gruzalski, J.D. Patterson, David J. Sellmyer
David Sellmyer Publications
Magnetic susceptibility and high-field magnetization measurements are presented for amorphous Zr40Cu60-xMx (M denoting Fe, Mn, Gd, and Tb) and Nb50Ni50-xFex, with x ranging from zero to about ten. The alloys for M=Gd, Tb, and Fe develop low-temperature ordered states that are characterized as spin glass like, whereas the Mn alloy exhibits no evidence of order down to 1.3 K. The magnetic properties of these alloys are discussed in terms of local random anisotropy, fluctuations in the interimpurity exchange interactions, extremely short electron-mean-free paths, antiferromagnetic interactions between the …
Magnetic Properties Of The Rare-Earth Intermetallics RGa2, T.H. Tsai, J.A. Gerber, John W. Weymouth, David J. Sellmyer
Magnetic Properties Of The Rare-Earth Intermetallics RGa2, T.H. Tsai, J.A. Gerber, John W. Weymouth, David J. Sellmyer
David Sellmyer Publications
The magnetic susceptibility (χ) of polycrystalline samples of RGa2, R=Ce, Pr, Nd, Gd, Tb, Dy, Ho, and Er, has been measured at low field, from 1.5 K to 300 K. The magnetization of these samples also has been measured up to 80 kOe at low temperatures. Antiferromagnetic behavior was observed for all the samples with Neel temperatures (TN) ranging from about 4.1 K for CeGa2 to about 14.8 K for TbGa2. Curie-Weiss fits to the high-temperature χ (T) data led to effective moments in good agreement with those expected for …
Magnetic Ordering In Amorphous Nd-Co, Gd-Co And Er-Co Alloys, J.A. Gerber, D.J. Miller, David J. Sellmyer
Magnetic Ordering In Amorphous Nd-Co, Gd-Co And Er-Co Alloys, J.A. Gerber, D.J. Miller, David J. Sellmyer
David Sellmyer Publications
Previous studies of magnetism in amorphous rare earth–transition metal alloys have emphasized alloys rich in transition metal. We report here results on three rare earth rich amorphous alloys: Nd64Co36, Gd65Co35, and Er65Co35. Low field susceptibility, χ, was measured for T in the range 4.2 K≤T≤300 K and magnetization was measured for 1.3≤T≤200 K and applied fields, H, of 0≤H≤80 kOe. Curie-Weiss fits were made to high temperature χ (T) data to determine average effective moments and Weiss temperatures. Hysteresis …
Ferromagnetic And Spin-Glass Ordering In Fe-Doped AuXPd1-X Alloys, E.R. Domb, David J. Sellmyer, T.M. Quick, R.J. Borg
Ferromagnetic And Spin-Glass Ordering In Fe-Doped AuXPd1-X Alloys, E.R. Domb, David J. Sellmyer, T.M. Quick, R.J. Borg
David Sellmyer Publications
Ferromagnetic and spin-glass ordering has been studied in (AuxPd1-x)1-cFec alloys for 0<~x<~1 and 0<~c≲0.06. Magnetic susceptibility, high-field magnetization, and Mössbauer measurements have been performed between liquid-helium and room temperature. For small x, the alloys are strongly exchange enhanced. Assuming that the local-moment-conduction-electron exchange coupling J is independent of x, and employing the Takahashi-Shimizu-Doniach-Wohlfarth theory, we obtain J=0.12 eV from the saturation moment versus host susceptibility data. The theory, however, fails to describe the interimpurity coupling that leads to magnetic order in the Pd-rich alloys. A simple phenomenological model, based on the ferromagnetic coupling of all the giant polarization clouds except those that are "isolated," gives qualitative agreement with the …