GIANT MAGNETOSTRICTION AND MAGNETOSTRICTION JUMPS IN SUPERCONDUCTING SINGLE-CRYSTALLINE LA1.85SR0.15CUO4

We have studied magnetostriction in single crystalline La1.85Sr0.15CuO 4 using the strain gauge technique in magnetic fields up to 12 T at te mperatures 4.2 K < T < 35 K. We have observed giant transverse magneto striction (of the order of 10(-4) at 4.2 K) for magnetic field B paral lel to c and longitudinal magnetostriction (of the order of 10(-5) at 4.2 K) for B perpendicular to c orientation. Pronounced jumps in trans verse magnetostriction have been observed in the temperature range bet ween 4.2 K and 8.5 K. Experimental magnetostriction results are compar ed with magnetization measurements using a vibrating sample magnetomet er and gradientometric Hall sensors measurements. The calculations wer e performed on the basis of a pinning-induced mechanism of magnetostri ction. The simple adiabatic theory seems to be insufficient to describ e the observed flux instabilities.