3 research outputs found
Magnetic Anisotropy And Magnetic Phase Transitions In Afe10mo2 (r=pr, Nd, Sm, Dy, Ho, Er, Tm)
No full textRFe10Mo2 (R=Pr, Sm, Nd, Dy, Ho, Er, Tm) intermetallics were investigated by studying the temperatureor field-induced spin-reorientation transitions (SRT's). The temperature dependence of the magnetic anisotropy field was determined by means of the singular point-detection technique for the polycrystalline samples of YFe10Mo2, NdFe10Mo2, DyFe10Mo2. and ErFe10Mo2. Main emphasis was given to the theoretical analysis of the magnetic anisotropy constants and the magnetic phase transitions. The temperature dependences of the rare-earth anisotropy constants were calculated using the single-ion model within linear theory. The applicability of the linear theory of the R anisotropy is discussed. It is shown that the accuracy of this theory increases considerably with increasing temperature. Fitting the experimental data, a set of the crystal field and exchange field parameters for the rare-earth R3+ ions was deduced. The observed SRT's and first-order magnetization processes (FOMP's) were explained and classified. FOMP-like transitions in PrFe10Mo2, HoFe10Mo2, and ErFe10Mo2, were identified. The temperature dependence of the FOMP fields was calculated for HoFe10Mo2 and ErFe10Mo2. The physical origin of a low-temperature anomaly in the magnetization process is discussed for SmFe10Mo2. The spin-reorientation transitions in ErFe10Mo2 and TmFe10Mo2 are determined to be of first order with a discontinuous jump of the magnetization. The SRT's detected in NdFe10Mo2 and DyFe10Mo2 are of second order. The calculated temperature dependences of the anisotropy fields for DyFe10Mo2 and NdFe10Mo2 are in good agreement with the experimental data over a wide temperature range. FOMP's are predicted at low temperatures for NdFe10Mo2, DyFe10Mo2, and TmFe10Mo2.551380388Kou, X.C., Grossinger, R., Wiesinger, G., Liu, J.P., De Boer, F.R., Kleinschroth, I., Kronmuller, H., (1995) Phys. Rev. B, 51, p. 8254Sinnecker, E.H.C.P., unpublishedErmolenko, A.S., Shcherbakova, Y.V., Ivanova, G.V., Belozerov, Y.V., (1990) Phys. Met. Metall., 70, p. 52Wang, Y.Z., (1993) J. Appl. Phys., 73, p. 6251Xu, X., Shaheen, S.A., (1993) J. Appl. Phys., 73, p. 6248Wang, Y.Z., (1994) J. Appl. Phys., 75, p. 6226Christides, C., Kostikas, A., Kou, X.C., Grossinger, R., Niarchos, D., (1993) J. Phys. C, 5, p. 8611Tucker, R., Xu, X., Shaheeen, S.A., (1994) J. Appl. Phys., 75, p. 6229Guslienko, K.Yu., Kou, X.C., Grossinger, R., (1995) J. Magn. Magn. Mater., 150, p. 383Xu, X., Shaheen, S.A., (1994) J. Appl. Phys., 76, p. 6754Stevens, K.W.H., (1952) Proc. Phys. Soc. London Ser. A, 65, p. 209Hu, B.-P., Li, H.-S., Coey, J.M.D., Gavigan, J.P., (1990) Phys. Rev. B, 41, p. 2221Kuz'min, M.D., Coey, J.M.D., (1994) Phys. Rev. B, 50, p. 12533Kuz'min, M.D., (1992) Phys. Rev. B, 46, p. 8219Tyablikov, S.V., (1965) Methods of Quantum Theory of Magnetism, , Nauka, MoscowAsti, G., Bolzoni, F., (1980) J. Magn. Magn. Mater., 20, p. 29Freeman, A.J., Desclaux, J.P., (1979) J. Magn. Magn. Mater., 12, p. 1
Zero-field phase transition from nearly uniform in-plane to out-of-plane magnetization state in soft magnetic cylinders
No full textVortex-state oscillations in soft magnetic cylindrical dots
No full textWe have studied magnetic vortex oscillations in soft submicron cylindrical dots with variable thickness and diameter by an analytical approach and micromagnetic simulations. We have considered two kinds of modes of the vortex magnetization oscillations: (1) low-frequency translation mode, corresponding to the movement of the vortex as a whole near its equilibrium position and (2) high-frequency vortex modes, which correspond to radially symmetric oscillations of the vortex magnetization, mainly outside the vortex core. The vortex translational eigenmode was calculated numerically in frequency and time domains for different dot aspect ratios. To describe the discrete set of vortex high-frequency modes we applied the linearized equation of motion of dynamic magnetization over the vortex ground state. We considered only radially symmetric magnetization oscillations modes. The eigenfrequencies of both kinds of the excitation modes are determined by magnetostatic interactions. They are proportional to the thickness/diameter ratio and lie in the GHz range for typical dot sizes
