Quenching and Recovery of Spin in Quasi-One-dimensional Itinerant Electron Magnet LaMn4Al8

Abstract

The electron correlation in the 3d heavy-electron compound with linear spin chains, LaMn 4 Al 8 , has been investigated. Like a similar compound, YMn 4 Al 8 , we found a broad maximum in the temperature dependence of the susceptibility. This is interpreted by assuming the presence of a narrow pseudogap with the width Δ≃280 K in the spin excitation spectrum, which leads to the quenching of spin at low temperatures. Anomalies in susceptibility, resistivity and thermal expansion data, observed below approximately 50 K in spite of the absence of any phase transition, suggest the recovery of spin and the development of short-range magnetic correlation in this low-temperature range. This is in contrast to the case of YMn 4 Al 8 . No apparent long-range ordering in spite of the markedly developed magnetic correlation is probably due to the one-dimensional nature of the Mn spin arrangement.