A STRUCTURAL PHASE-TRANSITION INDUCED BY AN EXTERNAL MAGNETIC-FIELD

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, La1-xSrxMnO3; 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.