%A T.L Phan
%A V.D Nguyen
%A T.A Ho
%A V. Khiem Nguyen
%A D. Thanh Tran
%A X. Phuc Nguyen
%A Duc Thang Pham
%A S.C. Yu
%J IEEE Transactions on Magnetics
%T Inhomogeneous ferromagnetism and spin-glass-like behaviour in (Nd1-xYx)0.7Sr0.3MnO3 with x = 0.21 - 0.35
%X The magnetic properties of polycrystalline ceramic samples (Nd1-xYx)0.7Sr0.3MnO3 with x = 0.21 - 0.35 were studied by means of dc magnetization and ac susceptibility measurements. Experimental results reveal a strong decrease of the ferromagnetic (FM)-paramagnetic phase-transition temperature (TC) from 97 to 65 K as increasing x from 0.21 to 0.35, respectively. There is magnetic inhomogeneity associated with short-range FM order. Particularly, the samples undergo a spin-glass (SG) phase transition at the so-called blocking temperature (TB) below TC, which shifts toward lower temperatures with increasing the applied field, Hex; TB → Tg (the SG phase-transition temperature) as Hex → 0. The existence of the SG behavior in these samples was also confirmed by frequency (f) dependences of the ac susceptibility. For the in-phase/real component, χ'(T), it shows a frequency-dependent peak at the SG freezing temperature (Tf); Tf → Tg as f → 0. Dynamics of this process were analyzed by means of the slowing down scaling law, τ/τ0 ∝ (Tf /Tg - 1)-zv, where τ0 and zv are the characteristic time and critical exponent, respectively. Fitting the experimental Tf (f) data to the scaling law gave the results of zv = 10.1-12.3 and τ0 = 10-21-10-15s. These values are different from those expected for canonical SG systems with zv = 10 and τ0 = 10-13s, revealing the cluster-SG behavior of (Nd1-xYx)0.7Sr0.3MnO3 samples. Notably, the increase in Y content leads to the shift of τ0 and zv values toward those of canonical SG systems, which is ascribed to an expansi- n of SG clusters.
%N 6
%P 2502204
%V 50
%D 2014
%I IEEE
%L SisLab1265