Electron irradiation effect on the flux creep in YBCO single crystal

The results of the magnetization measurements of single crystal of YBa2Cu3Oy with Tc = 91 К are adduced. The temperature, field and time dependences of the remanent magnetization МДТ, B, t) were obtained using VSM method for the temperature range from 4.2 К to 75 К for Н||с configuration. The single crystal has been irradiated by the fast electrons (E = 4 MeV) with fluences up to 2 • 1018 cm-2. The relaxation of Mr(t) obeys to the logarithmic law for the time interval t = 1 h for whole temperature range except the ~ 30 - 50 К interval for starting and irradiated states. After irradiation the Jc decrease despite the flux creep reduction. The irradiation become less effective at high temperatures. The results are discussed in frame of conventional flux creep theory and of the interaction model of radiation defects with the background ones

Flux creep in irradiated Bi2Sr2CaCu2Oy single crystal

We report our measurements of the magnetization relaxation Mr(t) in irradiated Bi2Sr2CaCu2Oy (Bi - 2212) single crystal at Amii temperatures and calculate the pinning potential U0 in a wide temperature range. The observed nonlogarithmic time I kay has been discussed in framework of dimensional ЗД - 2Д crossover model

Critical current enhancement and flux pinning in irradiated BKBO single crystal

Measurements of magnetization versus temperature, field and time are performed using VSM technique in single crystal of Ba058K042 BiO3 (BKBO) irradiated by fast electrons (E = 4 MeV) and maximum fluency of 2 1010 cm- ' for a fields up to 6 T in the range from 4.2 K to 25 K. The results are discussed in the terms of the stronger flux pinning in the crystal with radiation defects

Magnetic Properties of EuBaCo2\text{}_{2}O5.5\text{}_{5.5} Single Crystals

The static magnetization of the EuBaCo$\text{}_{2}$O$\text{}_{5.5}$ single crystals was measured from helium to room temperatures for two configurations of the applied field: parallel and perpendicular to the c-axis. The compound is antiferromagnetic from helium temperature to about 210 K. In low temperature region (below 45 K) the antiferromagnetism coexists with a spin-glass-like state. The metamagnetic field-induced phase transition was observed in the antiferromagnetic phase for magnetic field applied perpendicular to the c-axis. The spontaneous phase transition from antiferromagnetic to weak ferromagnetic phase was established to be of the first order. This transition is accompanied by the appearance of the intermediate state. The weak ferromagnetic phase exists up to T$\text{}_{c}$=240 K

Magnetic properties lithium-doped manganite single crystals

Magnetic and resistivity properties of La₁₋xLixMnO₃ single crystals with the perovskite structure at lithium concentrations x=0.06 and 0.2 are investigated over a broad temperature range at fields of up to 50 kOe. The Curie temperature is TC=90 K (x=0.06) and 300 K (x=0.2), respectively. The electrical resistance of the single crystal with x=0.06 increases steadily with temperature decrease, while the crystal with x=0.2 exhibits a magnetoresistance effect of ~ 8% at an external field of 9 kOe. The different dependence of the magnetizations MFC and MZFC of the sample with lower lithium content in the temperature range below TC is associated with the formation of a cluster glass and is caused by high coercivity and magnetic anisotropy of the crystal