1. ^*Joint Research Center for Atom Technology (JRCAT), Tsukuba, Ibaraki 305, Japan
2. ^†Department of Physics, University of Tokyo, Tokyo 113, Japan

Abstract

A VAST number of compounds are known that exhibit structure transformations in response to changes in temperature, pressure and/or composition. One such example is the family of perovskites, La_1-xSr_xMnO₃3 for a limited range of compositions (x), they undergo a structural phase transition from an orthorhombic to a rhombohedral form with increasing temperature^{1, 2}. These compounds are also ferromagnetic, a property that arises from coupling between the charge carriers and localized spin moments of the manganese ions^3–7. Here we show that, through careful tuning of the composition, the local spin moments and the charge carriers can in turn be coupled strongly to changes in the structure. For x = 0.170, the crystal structure of the compound can be switched—reversibly or irreversibly, depending on the temperature—by application of an external magnetic field.