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

Giant volume magnetostriction, reached similar to 6 x 10(-4) in magnetic field 8.2 kOe, is found in La1-xMxMnO3( M = Ba,Sr, Ca, Ag) manganites near Curie-point T-C. 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 sigma (2), where A = La1-xMx. (c) 2007 Elsevier B. V. All rights reserved.