Field-dependent roughness of domain walls in a Pt/Co/Pt magnetic thin film

CORTÉS BURGOS, MARÍA JOSÉ; GURUCIAGA, PAMELA C.; JORDÁN, DANIEL; QUINTEROS, CYNTHIA P.; AGORITSAS, ELISABETH; CURIALE, JAVIER; GRANADA, MARA; BUSTINGORRY, SEBASTIAN

San Carlos de Barilche

Workshop; International Workshop on Spintronics (SPIN Argentina 2022); 2022

The creep motion of domain walls (DWs) driven by external fields in magnetic thin films isdescribed by universal features related to the underlying depinning transition. The roughnessof the DWs can be described by the displacement correlation function B(r) ~ B0 r2z. One keyparameter in this description is the roughness exponent z characterizing the growth offluctuations of the domain wall position with its longitudinal length scale r. The roughnessamplitude B0, which gives information about the scale of fluctuations, however, has receivedless attention. Albeit their relevance, experimental reports of the roughness parameters, bothexponent and amplitude, are scarce. We report here experimental values of the roughnessparameters for different magnetic field intensities in the creep regime at room temperature fora Pt/Co/Pt thin film [1]. The mean value of the roughness exponent is z = 0.74, and we showthat it can be rationalized as an effective value in terms of the known universal valuescorresponding to the depinning and thermal regimes [2]. In addition, we show that theroughness amplitude presents a significant increase with decreasing field. These resultscontribute to the description of DW motion in disordered magnetic systems. References[1] C. P. Quinteros et al., “Impact of growth conditions on the domain nucleation and domain wall propagationin Pt/Co/Pt stacks”, J. Phys. D: Appl. Phys. 54, 015002 (2020). https://iopscience.iop.org/article/10.1088/1361-6463/abb849[2] M. J. Cortés Burgos et al., “Field-dependent roughness of moving domain walls in a Pt/Co/Pt magnetic thinfilm”, Phys.Rev.B. 104, 144202 (2021). https://journals.aps.org/prb/abstract/10.1103/PhysRevB.104.144202