Aligning nano-scale crystals in bulk materials

Crystal orientation determines various material performances including magnetic,electrical,and mechanical properties.However,achieving the alignment of nano-grains along a specific crystallographic orientation in bulk materials remains a formidable challenge.Departing from conventional approaches using polycrystalline materials,we report a strategy to overcome this challenge by deliberately introducing strain-energy anisotropy to select oriented nucleation/growth of crystals in amorphous materials.To demonstrate its efficacy,we employed ferromagnetic materials as a proof of concept.Using our approach,a range of previously inaccessible bulk ferromagnetic nanomaterials with strong c-axis orientation have been created.The resulting bulk oriented nano-grained magnets exhibit a high energy density,168 k J m-3for Sm Co7and 235.2 k J m-3for Pr Co5ferromagnets,greatly surpassing that of their state-of-the-art counterparts with 23%-62%enhancement.Our strategy is general and applicable to other material systems,including thermoelectric,piezoelectric,and ferroelectric materials,to achieve the desired oriented nano-grains for technological applications.