Pressure-induced spin and charge transport in La1.25Sr1.75Mn2O7 single crystal

Abstract

Abstract We investigated the effect of uniaxial and hydrostatic pressure on resistivity and ac-magnetic susceptibility of two-dimensional layered manganite, La 1.25 Sr 1.75 Mn 2 O 7 (LSMO125) to investigate the lattice effect on magnetic and electronic properties. Asymmetric role of uniaxial pressure, || and ⊥ to c -axis on the spin flop and charge transport has been revealed while comparing hydrostatic pressure. Uniaxial pressure along c -axis increases metal–insulator transition temperature ( T MI ) and ferromagnetic ordering temperature ( T C ), whereas it decreases the resistivity along ab-plane ( ρ ab ). In contrast to pressure along c -axis, T MI and T C decrease, whereas the resistivity along c -axis ( ρ c ) increases with pressure || to ab-plane. ρ c / ρ ab is quite large, increasing with pressure and shows a peak at around T MI . Uniaxial pressure behaviour is strongly related to the Mn–O–Mn linkage between MnO 2 layers and the spin reorientation from the apical axis to the basal plane and vice versa with pressure. Both ρ ab and ρ c decrease whereas T MI and T C increases under hydrostatic pressure. Influence of spin and charge on magnetic and electrical properties under hydrostatic pressure are explained by pressure-induced cant between the MnO 2 bilayers and variation in bond lengths. The different pressure driving rates of T MI while measuring ρ ab and ρ c confirms that there is a strong competition between the in and out plane components under hydrostatic pressure.