Zhang Mingang

Room-Temperature Ferromagnetism in Fe/Sn-Codoped In2O3 Powders and Thin Films

Fe/Sn-codoped In2O3 powders and films are prepared by a vacuum annealing process and a pulsed laser deposition technique, respectively. The structural and magnetic properties of the samples are investigated. The obvious room-temperature ferromagnetism is observed in both (In0.92Fe0.05Sn0.03)(2)O-3 powders and films, but their magnetic behaviors are very different. The ferromagnetism of the vacuum-annealed powders is partially due to precipitated Fe3O4 impurity. By contrast, the ferromagnetism of the films is intrinsic and does not originate from any magnetic impurity, as confirmed by the extensive x-ray absorption spectroscopy and magnetization studies.

Martensitic transformation and giant magnetic entropy change in Ni42.8Mn40.3Co5.7Sn11.2 alloy

The crystal structure, phase transition, and magnetocaloric effect in Ni42.8Mn40.3Co5.7Sn11.2 alloy are investigated by structure analysis and magnetic measurements. A large magnetic entropy change of 45.6 J/kgK is obtained at 215 K under a magnetic field of 30 kOe (1 Oe = 79.5775 Am−1). The effective refrigerant capacity of Ni42.8Mn40.3Co5.7Sn11.2 alloy reaches 72.1 J/kg under an applied field changing from 0 to 30 kOe. The external magnetic field shifts the martensitic transition temperature about 3–4 K/10 kOe towards low temperature, indicating that magnetic field can retard the phase transition to a certain extent. The origin of large magnetic entropy change is discussed in the paper.

The Texture and Topography of Melt-Spun Ribbons of Nd 2 Fe 14 B/α-Fe Two-Phase Permanent Magnetic Alloys

The texture and topography of melt-spun ribbons of nanocrystalline two-phase permanent magnetic alloys was studied by X-ray diffractometry and scanning probe microscopy. It was found that a pronounced preferred orientation existed in the free-side surface of melt-spun ribbons. Compared with ternary NdFeB alloy, adding Dy+Ga can increase the texture in free-side surface and refine the microstructure and topography of the ribbons.