Subject classification: 61.66.Fn; 62.40.+i; 75.30.Kz; 75.30.Vn; S10.15 La 0.95 K 0.05 MnO 3 has been studied with reference to the internal friction, electrical resistance and ac magnetic susceptibility. Large magnetoresistance (MR) exists in a wide temperature range (20-275 K) in La 0.95 K 0.05 MnO 3 specimens at a small magnetic field (0.3 T). The resistance has a sharp peak at about 265 K, and the MR has a sharp peak at about 259 K. The internal friction measurement reveals a peak at about 268 K, accompanied with a minimum of elastic modulus. The position of the peak in Q --1 does not shift with frequency, but the height of the peak in Q --1 decreases with increasing frequency, which is a general character of the low frequency internal friction associated with the phase transition. The apparent activation energy of the phase transition E ap was obtained as 0.53 eV.

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