Magnetostriction and a magnetoelastic mechanism for the irreversible behavior of the magnetoresistance in layered antiferromagnets

A theoretical model is proposed for describing the irreversible behavior of the magnetoresistance of underdoped cuprates RBa2Cu3Ox in an external magn etic field over a wide range of temperatures. The underlying assumption of the model is a magnetoelastic mechanism for the formation of the domain str ucture of the collinear antiferromagnet owing to long-range "stray" fields resulting from the difference in the elastic properties of the bulk and sur face. The law of corresponding states in reduced variables is established f or the magnetoresistance, external magnetic field, and temperature, and the temperature dependence of the "monodomainization" field, the field at whic h the sample is brought to a single-domain state, is determined. The theore tical relations obtained give a comprehensive description of the features o f the magnetoresistance of RBa2Cu3Ox and are in quantitative agreement with the experimental data. (C) 2001 American Institute of Physics.