Composition dependence of the spin wave stiffness parameter in La(sub 1-x)Ca(sub x)MnO(sub 3) CMR materials.

Rhyne, J. J. ; Kaiser, H. ; Stumpe, L. ; Mitchell, J. F. ; Mccloskey, T. ; Chourasia, A. R.

Technical Information Center Oak Ridge Tennessee

关键词: Spin waves;    Lanthanum oxides;    Calcium oxides;    Magnetic materials;    Chemical composition;   

RP-ID  :  DE2001757538

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Long wavelength spin waves in La(1-x)Ca(x)MnO(3)CMR materials exhibit conventional Heisenberg dispersion (E = D1(sup 2) + delta), but with an anomalous temperature dependence for the spin dispersion parameter D. For x approx. 0.33, near the optimum CMR composition, D remains approximately 50% of its T = 0K value before exhibiting a near-first-order transition at T(sub c), instead of following the expected power law decrease as T approaches T(sub c-). No temperature hysteresis was observed in either D or in the magnetization. Compositions with x = 0.40 and 0.45 show more conventional temperature renormalization.