Spin-glass state of (Nd,La)(0.5)Sr1.5MnO4

We studied the low-temperature magnetic properties of single-crystal (Nd1-x Lax)(0.5)Sr1.5MnO4 using x and de susceptibility, and magnetization measure ments. From this study, we found that Nd-doped samples showed the sign of a different magnetic state below 20 K. a peak in the ac susceptibility signa ling the state shows a strong frequency dependence, indicative of the metas table nature of the transition. This metastable nature of the transition is also borne out by the nonzero isothermal remnant magnetization and the dif ference in the peak temperatures determined from ac and de susceptibility. A further evidence for this conclusion comes from the absence of magnetic p eaks at low temperature in our neutron-diffraction pattern.