La_(5/6)Li_(1/6)MnO_3的低频内耗研究

Low frequency study phase separation in La_(5/6)Li_(1/6)MnO_3

研究了样品La5/6Li1/6MnO3的内耗、直流电阻、交流磁化率.在75—245K的温度范围内,在0.3T的磁场下该样品有明显的磁阻(MR)效应.测量到两个电阻峰(Tp1=224K,Tp2=169K)和一个MR峰(T=218K).内耗(Q-1)测量中发现两个峰(PL=169K,PH=224K)和模量软化;并且内耗峰温与频率无关、内耗峰值与频率成反比.最终,提出在样品中存在相分离的观点.

La_(5/6)Li_(1/6)MnO_3 has been studied with reference to the internal friction (Q^(-1)), electrical resistivity and AC magnetic susceptibility. Large magnetoresistance ratio (MR) exists in a wide range temperature (75-245 K) in La_(5/6)Li_(1/6)MnO_3 specimens at a small magnetic field (0.3 T). Two resistivity peaks (T_(p1)=224 K,T_(p2)=169 K) and a MR peak (T=218 K) are observed. Accompanied with the local minimum of elastic modulus, the internal friction measurement reveals two peaks at about 169 K and 224 K. The position of the peak in Q^(-1) does not shift with the frequency, while the height of the peak in Q^(-1) decreases with the frequency increase. From above experiments, we draw the conclusion that there is phase separation in the sample.