Creating magnetism takes much longer than destroying it

Fig.1: Non-magnetic state of iron-rhodium (FeRh) when illuminated by a laser pulse
Researchers at the Paul Scherrer Institute are finding out how long it takes to establish magnetism and how this happens. Establishing a magnetically ordered phase in the metallic alloy iron-rhodium takes much longer than the reverse process of demagnetization. This fact was established by researchers of the Paul Scherrer Institute (PSI), Switzerland, together with colleagues of an international collaboration. Magnetism is established in a two-step process. Initially, small magnetic regions form, but have random orientation. Subsequently, these regions rotate until they all have a common orientation. This is reported in an article which has recently been published in the renowned journal “Physical Review Letters”. The result comes from basic research, but has relevance for the computer industry, as it shows which processes limit the speed of magnetic data storage and where improvements might be made.

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