Probing fractal magnetic domains on multiple length scales in Nd2Fe14B

Using small-angle neutron scattering, we demonstrate that the complex magnetic domain patterns at the surface of Nd2Fe14B, revealed by quantitative Kerr and Faraday microscopy, propagate into the bulk and exhibit structural features with dimensions down to 6 nm, the domain wall thickness. The observed fractal nature of the domain structures provides an explanation for the anomalous increase in the bulk magnetization of Nd2Fe14B below the spin-reorientation transition. These measurements open up a rich playground for studies of fractal structures in highly anisotropic magnetic systems.Comment: Accepted for publication in Phys. Rev. Lett. (4 pages, 4 figures

Giant volume magnetostriction in the Y 2

An investigation of the Y2Fe17 compound belonging to the class of intermetallic alloys of rare-earth and 3d-transition metals is presented. The magnetization, magnetostriction, and thermal expansion of the Y2Fe17 single crystal were studied. The forced magnetostriction and magnetostriction constants were investigated in the temperature range of the magnetic ordering close to the room temperature. The giant field induced volume magnetostriction was discovered in the room temperature region in the magnetic field up to 1.2 T. The contributions of both anisotropic single-ion and isotropic pair exchange interactions to the volume magnetostriction and magnetostriction constants were determined. The experimental results were interpreted within the framework of the Standard Theory of Magnetostriction and the Landau thermodynamic theory. It was found out that the giant values of the volume magnetostriction were caused by the strong dependence of the 3d-electron Coulomb charge repulsion on the deformations and width of the 3d-electron energy band

Rotational Magnetocaloric Effect in the Er2Fe14B Single Crystal

The adiabatic temperature change ΔTad and the isothermal entropy change ΔSm were measured in a Er2Fe14B single crystal in the temperature range of 250-370 K under a magnetic field change of Δμ0H = 1.9 T. The magnetic field was applied along the crystallographic axes a and c. Under adiabatic conditions, the application of a 0.5 T field along the c-direction of the Er2Fe14B single crystal leads to a negative ΔTad at temperatures below the spin-reorientation temperature TSR = 323 K. In this case, the maximum ΔTad reaches -0.9 K in the temperature range of 270-280 K. Along the a-direction, the magnetocaloric effect above TSR is positive, and ΔTad reaches 0.68 K in the magnetic field 0.5 T at the temperatures of 320-330 K. Under isothermal conditions, the maximal magnetic entropy change is -0.86 J kg-1K-1 at 328 K when the magnetic field is applied along the a-direction and ΔSm = 1.27 J kg-1K-1 at 275 K if the single crystal is magnetized along the c-axis

Giant volume magnetostriction in the Y2Fe17 single crystal at room temperature

Under the terms of the Creative Commons Attribution 3.0 Unported License.An investigation of the Y2Fe17 compound belonging to the class of intermetallic alloys of rareearth and 3d-transition metals is presented. The magnetization, magnetostriction, and thermal expansion of the Y2Fe17 single crystal were studied. The forced magnetostriction and magnetostriction constants were investigated in the temperature range of the magnetic ordering close to the room temperature. The giant field induced volume magnetostriction was discovered in the room temperature region in the magnetic field up to 1.2 T. The contributions of both anisotropic singleion and isotropic pair exchange interactions to the volume magnetostriction and magnetostriction constants were determined. The experimental results were interpreted within the framework of the Standard Theory of Magnetostriction and the Landau thermodynamic theory. It was found out that the giant values of the volume magnetostriction were caused by the strong dependence of the 3delectron Coulomb charge repulsion on the deformations and width of the 3d-electron energy band.The work was supported by RFBR Grant Nos. 13-02-00916 and 12-02-31516.Peer reviewe

The magnetic domain structure of DyFe11Ti single crystals.

4 figures.The magnetic domain structure (DS) on (1 1 0)-, (0 0 1)- and arbitrary-oriented planes of DyFe11Ti single crystals is investigated in the temperature region from room temperature down to 4.2 K. The role of magneto-elastic interaction and deviation from stoichiometric ratio 1:12 in DS formation and spin-reorientation transitions is discussed.Peer reviewe