Pengaruh Subtitusi Unsur Cu terhadap Sifat Kelistrikan dan Kemagnetan dari Material Perovskite Ca0.9La0.05Bi0.05Mn1-xCuxO3 (x = 0, 0.025, 0.05, 0.075, 0.1) = The Effect Of Cu Subtitution On The Electrical And Magnetic Properties Of Pervoskite Materials Ca0.9La0.05Bi0.05Mn1-xCuxO3 (x = 0, 0.025, 0.05, 0.075, 0.1)