Galvanomagnetic properties of atomically disordered compounds YBa2Cu3O7

The temperature dependences of the Hall coefficient R-H and magnetoresistan ce MR of polycrystalline samples of YBa2Cu3O7 disordered with fast neutrons (fluence Phi = 2 x 10(19) cm(-2)) retain anomalous properties (linear temp erature dependence of the Hall concentration n(H) = 1/(R(H)e) and the negat ive value of R-H) characteristic of ordered high-T-c compounds despite the fact that their conductivity is not metallic. This behavior is explained by the fact that two electron phases with conduction in localized and metalli c states coexist in disordered samples. The concentration of the metallic p hase is below the percolation threshold; therefore, the conductivity of suc h a system is typical of insulators, whereas R-H and MR exhibit temperature dependences characteristic of the metallic phases but renormalized in magn itude.