Electrical and magnetic properties of Ca1-xLaxRuO3

The electrical resistivity rho and the magnetic susceptibility chi were mea sured for the sintered samples of Ca1-xLaxRuO3 (0 less than or equal to x l ess than or equal to 1) (Lax) and Ca1-xPrxRuO3 (x less than or equal to 0.2 ). The temperature coefficient d rho/dT is positive at 300 K for all the sa mples, but rho increases logarithmically with decreasing temperature as for the Kondo effect except for the end members x = 0 and 1. The Curie-Weiss l ike chi was found for Lax, and the absolute value of the antiferromagnetic Weiss temperature increases with a: until 0.3 and then decreases. For La0.3 the Curie-type chi appeared overlapping the Curie-Weiss chi below 50 K, an d there was no clear peak in chi down to 5 K. Tile resistance anomaly may h ave been caused either by the Kondo scattering; or a localization effect an d/or an electron-electron interaction under the random distribution of hete ro-valent cations.