On the electrical transport properties of Cr thin films with confined spin density waves

EDUARDO OSQUIGUIL; LEANDRO TOSI; ENRIQUE KAUL; CARLOS A. BALSEIRO

Capital Federal

Workshop; X-LAW3M Latin American Workshop on Magnetism; 2013

We present an experimental study of the resistivity rho and Hall coefficient R_H of epitaxial (100) thin Cr films of different thicknesses as a function of temperature T and applied magnetic field H. We show that the quantization due to the confinement of the incommensurate spin density waves (ISDW) within the film thickness, is responsible for two main peculiarities: i) an hysteretic behavior of rho(T) and R_H in certain temperature region that is film thickness dependent, and ii) a characteristic noise in rho(T) which appears within the same temperature region where the hysteresis is observed. We explain the hysteretic behavior in terms of a first order transition between domains of ISDW´s with N and N+1 nodes. At each temperature within the hysteresis region, it exists a different distribution of such domains with different sizes, local energies, and number of nodes, which give rise to the noise observed in rho(T). Finally we also show that the resistivity minimum observed for all studied thicknesses at low temperatures, is not due to a Kondo-like contribution to the scattering time, nor to resonant impurity scattering generated by non-magnetic impurities and/or vacancies, but has it´s origin in an imperfect nesting of the Q vectors which originate the ISDW.