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The textured Pr2Fe14B nanoflakes were produced by surfactant-assisted ball milling (SABM). Single phase tetragonal structure was characterized for the samples before and after SABM by X-ray diffraction (XRD). The thickness and length of the as-milled flakes are mainly in the range of 50-150 nm and 0.5-2μm, respectively. For the field-aligned Pr2Fe14B nanoflakes, the out-of-plane texture (the easy magnetization direction (EMD) along the c-axis) is indicated from the increasing (00l) peaks in the XRD patterns. SEM image demonstrates that the EMD is parallel to flaky surface, which is different from the RCo5 (R=rare earth) system with EMD perpendicular to the surface. We propose a hypothesis that the easy glide planes are related with the area of crystal planes. In addition, a large coercivity Hc=3.9 kOe is observed in the Pr2Fe14B flakes with strong texture. [ABSTRACT FROM AUTHOR]

The effect of the milling time on the structure, morphology, coercivity, and remanence ratio of textured PrCo5 nanoflakes produced by low power surfactant-assisted ball milling (SABM) was investigated. The X-ray powder diffraction (XRD) patterns indicate that the SABM PrCo5 samples are all CaCu5-type hexagonal structure. The average grain size is smaller than 10 nm when the SABM time is equal to or longer than 5.5 h. The thickness of nanoflakes is mainly in the range of 50-100 nm while the length is 0.5-5 μm when the SABM time reaches 8 h. For the field-aligned PrCo5 nanoflakes, the out-of-plane texture is indicated from the increasing (0 0 l) peaks in the XRD patterns, and the easy magnetization direction is perpendicular to the flake surface. The strong texture of PrCo5 nanoflakes leads to a large coercivity Hc (7.8 kOe) and obvious anisotropic magnetic behaviors for the aligned samples. [ABSTRACT FROM AUTHOR]

Nd2Fe14B films with easy magnetization axis perpendicular to the film plane were grown onto Tabuffered piezoelectric (011)-0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) substrates using a magnetron sputtering technique. The film retains good permanent magnetic properties, with coercivities up to 1.4 T and spin reorientation near 150 K. Our investigations demonstrated that the converse piezoelectric effect generated by an electric field across the PMN-PT substrate can rotate the angle of spin reorientation of the Nd2Fe14B films, resulting in a considerable manipulation of magnetization by the electric field at temperatures below 150 K. The ratio of magnetization change reaches 30% in a magnetic field of 2 T when an electric field of 6 kV/cm is applied at 30 K. With increasing temperature, the electric field-induced tunability of magnetization decreases. These observations of permanent magnetic properties and electrically controlled magnetization effects make the Nd2Fe14B/PMN-PT heterostructure attractive for exploring multifunctional magnetic/electric devices. [ABSTRACT FROM AUTHOR]

A considerable magnetic entropy change has been observed in Ni[sub 51.5]Mn[sub 22.7]Ga[sub 25.8] alloys under a field of 0.9 T. This change originates from a sharp magnetization jump which is associated with a martensitic to austenitic structure transition. The large low field entropy change and the adjustable martensic-austensic transition temperature indicate a great potential of Ni-Mn-Ga as working materials for magnetic refrigerants in a wide temperature range. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]