Giant volume magnetostriction and its connection with colossal magnetoresistance and lattice-softening La1−xMxMnO3 (M=Ca, Ag, Ba, Sr)

Giant volume magnetostriction, reached 6X10-4 in magnetic field 8.2kOe, is found in La1-xMxMnO3 (M=Ba, Sr, Ca, Ag) manganites near Curie-point TC. Volume magnetostriction omega and magnetoresistance exhibit similar dependence on temperature and magnetic field in TC region that is explained by the presence in these compounds of magnetic two-phase ferromagnetic-antiferromagnetic state due to strong s-d and/or d-d exchange. Maximum |omega|-value depends from radius of M-cation: it is larger the larger the difference |RA-RLa3+| and A-cation size variance sigma2, where A=La1-xMx.