Giant Low-Field Magnetocaloric Effect at Sub-Kelvin Temperatures in Ferromagnetic NH4GdF4 - Qing Guo; Weijun Ren; Peng Liu; Jiwei Yao; Junsen Xiang; Kun Zhang; Yanxu Wang; Loku Singgappulige Rosantha Kumara; Xiaolei Wang; Wei Li; Bing Li (Journal of the American Chemical Society, 2025)