Physical Sciences and Mathematics Commons^™

Surface Magnetoelectric Effect In Ferromagnetic Metal Films, Chun-Gang Duan, Julian P. Velev, Renat F. Sabirianov, Zigiang Zhu, Junhao Chu, Sitaram Jaswal, Evgeny Y. Tsymbal

Physics Faculty Publications

A surface magnetoelectric effect is revealed by density-functional calculations that are applied to ferromagnetic Fe(001), Ni(001), and Co(0001) films in the presence of an external electric field. The effect originates from spin-dependent screening of the electric field which leads to notable changes in the surface magnetization and the surface magnetocrystalline anisotropy. These results are of considerable interest in the area of electrically controlled magnetism and magnetoelectric phenomena.

The Surface Stability Of Cos2(100), Ning Wu, Renat F. Sabirianov, Chun-Gang Duan, Wai-Ning Mei, David Wisbey, Ya B. Losovyj, M. Manno, Christopher Leighton, En Cai, Jiandi Zhang, Peter Dowben

Physics Faculty Publications

The stability of various possible terminations of the CoS2 (1 × 1) surface have been explored and theoretical expectations are found to agree with experiment. With extensive annealing, there is a phase separation at the (100) surface of CoS2. Sulfur segregation to the surface leads to a significant change in the largely sulfur bands due to changes in the hybridized bands, with cobalt. Resonant photoemission spectra indicate clearly that the hybridized cobalt and sulfur bands, characteristic of the CoS2 bulk, lie at higher binding energies than those of segregated sulfur layers. This is discussed in terms of the stability of …

Electronic And Magnetic Properties Of Endohedrally Doped Fullerene Mn@C60: A Total Energy Study, Guangping Li, Renat F. Sabirianov, Jing Lu, Xiao Cheng Zeng, Wai-Ning Mei

Physics Faculty Publications

We perform total energy calculations on a manganese atom encapsulated inside a C₆₀ cage using density functional theory with the generalized gradient approximation through three optimization schemes and along four paths inside the cage. We find that when Mn is located in the central region, its electronic and magnetic properties are not exactly the same as those of a free Mn atom due to weak coupling between Mn and the cage. As Mn is shifted toward to the edge, the total energy and spin start to change significantly when Mn is situated about one-third of the way between the …

Theory Of The Piezomagnetic Effect In Mn-Based Antiperovskites, Pavel Lukashev, Renat F. Sabirianov, Kirill Belashchenko

Physics Faculty Publications

Recent experimental and theoretical studies of the magnetoelectric ME effect in the nanocomposite structures and in laminates show an enhanced ME coefficient. These materials combine piezoelectric properties of the paramagnetic phase and piezomagnetic properties of the magnetic phase. We propose to fabricate heterostructures formed by piezoelectric materials and magnetic antiperovskites as magnetoelectric materials. We show that the magnetic structure of antiperovskite, such as Mn3GaN, can be controlled by a small applied biaxial strain. The lowering of symmetry with the strain causes the local magnetic moments of Mn atoms to rotate from the trigonal 5g structure with symmetric curl of spin …

Local Structures Surrounding Zr In Nanostructurally Stabilized Cubic Zirconia: Structural Origin Of Phase Stability, Y. L. Soo, P. J. Chen, S. H. Huang, T. J. Shiu, T Y. Tsai, Y. H. Chow, Y. C. Lin, S. C, Weng, S. L. Chang, G. Wang, Chin Li Cheung, Renat F. Sabirianov, Wai-Ning Mei, Fereydoon Namavar, Hani Haider, Kevin L. Garvin, J. F. Lee, H. Y. Lee, P. P. Chu

Physics Faculty Publications

Local environment surrounding Zr atoms in the thin films of nanocrystalline zirconia (ZrO₂) has been investigated by using the extended x-ray absorption fine structure (EXAFS) technique. These films prepared by the ion beam assisted deposition exhibit long-range structural order of cubic phase and high hardness at room temperature without chemical stabilizers. The local structure around Zr probed by EXAFS indicates a cubic Zr sublattice with O atoms located on the nearest tetragonal sites with respect to the Zr central atoms, as well as highly disordered locations. Similar Zr local structure was also found in a ZrO₂ nanocrystal …

Tailoring Magnetic Anisotropy At The Ferromagnetic/Ferroelectric Interface, Chun-Gang Duan, Julian P. Velev, R. F. Sabirianov, W. N. Mei, S. S. Jaswal, E. Y. Tsymbal

Physics Faculty Publications

It is predicted that magnetic anisotropy of a thin magnetic film may be affected by the polarization of a ferroelectric material. Using a Fe∕BaTiO3 bilayer as a representative model and performing first-principles calculations, we demonstrate that a reversal of the electric polarization of BaTiO3 produces a sizable change in magnetic anisotropy energy of Fe films. Tailoring the magnetic anisotropy of a nanomagnet by an adjacent ferroelectric material may yield entirely new device concepts, such as electric-field controlled magnetic data storage.

We thank Ruqian Wu for fruitful discussions. This work was supported by the NSF and the Nanoelectronics Research Initiative through …