Sendetskyi, Oles Scagnoli, Valerio Leo, Naëmi Anghinolfi, Luca Alberca, Aurora Lüning, Jan Staub, Urs Derlet, Peter Michael Heyderman, Laura Jane 2019-06-20 Critical behavior is very common in many fields of science and a wide variety of many- body systems exhibit emergent critical phenomena. The beauty of critical phase transitions lies in their scale-free properties, such that the temperature dependence of physical parameters of systems differing at the microscopic scale can be described by the same generic power laws. In this work we establish the critical properties of the antiferromagnetic phase transition in artificial square ice, showing that it belongs to the two-dimensional Ising universality class, which extends the applicability of such concepts from atomistic to mesoscopic magnets. Combining soft x-ray resonant magnetic scattering experiments and Monte Carlo simulations, we characterize the transition to the low-temperature long-range order expected for the artificial square-ice system. By measuring the critical scattering, we provide direct quantitative evidence of a continuous magnetic phase transition, obtaining critical exponents which are compatible with those of the two-dimensional Ising universality class. In addition, by varying the blocking temperature relative to the phase transition temperature, we demonstrate its influence on the out-of-equilibrium dynamics due to critical slowing down at the phase transition. application/pdf https://folia.unifr.ch/global/documents/308024 https://folia.unifr.ch/documents/308024/files/alb_cmt.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevB.99.214430 info:eu-repo/semantics/openAccess License undefined Physical Review B. - 2019, vol. 99, no. 21, p. 214430 info:eu-repo/classification/udc/53 Continuous magnetic phase transition in artificial square ice http://purl.org/coar/resource_type/c_6501