Ni-oxide-based films were prepared by cathodic electrodeposition and, for comparison, by reactive sputtering. They were characterised by cyclic voltammetry, spectrophotometry (showing electrochromism), and infrared absorption spectroscopy. Magnetic measurements, performed at low temperatures using SQUID technology, exhibited a well-defined Curie Weiss behavior with a transition temperature that was depressed by proton extraction. These data give clear evidence that magnetic measurements can serve as a useful and versatile tool for probing the basic properties of certain electrochromic thin films.