Different symmetry breaking ways determine various magnetization switching modes driven by spin–orbit torques (SOT). For instance, an applied or effective field parallel to applied current is indispensable to switch magnetization with perpendicular anisotropy by SOT. Besides of this mode, here we experimentally demonstrate a distinct field-free switching mode in a T-type magnetic system with structure of MgO/CoFeB/Ta/CoFeB/MgO where a perpendicular layer with tilted easy axis was coupled to an in-plane layer with a uniaxial easy axis. Current was applied orthogonal to both easy axes and thus also normal to an in-plane effective field experienced by the perpendicular layer. Dynamic calculation shows perpendicular layer could be switched at the same time as the in-plane layer is switched. These field-free switching modes realized in the same T-type magnetic system might expedite the birth of multi-state spin memories or spin logic devices which could be operated by all electric manners.

Carbon fibre reinforced SiOC composites (denoted as C fibre /SiC fillers /SiOC) were prepared by slurry coating and polymer infiltration pyrolysis (PIP) process. Low viscosity liquid polysiloxane (PSO) and SiC powder were combined at a 1 : 1 weight ratio to produce a blend (S-PSO), which was employed as matrix source. Heat treated carbon fibre fabric was adopted as the reinforcement. The lamination process was determined on the basis of cure and rheology investigations on S-PSO. The effects of PIP cycles and temperature of heat treatment of the carbon fibre on the mechanical properties of C fibre /SiC fillers /SiOC were examined. The results indicate that composites using carbon fibres annealed at 1700uC as reinforcement reached a maximum flexural strength of 300 MPa after six PIP cycles. The resistance of the C fibre /SiC fillers / SiOC composite to oxidation was also evaluated. Without any protective coatings, the composite retained 60% of its strength after oxidation at 800uC for 3 h in a static air environment.