Fast barrier-free switching in synthetic antiferromagnets.

We analytically solve the Landau-Lifshitz equations for the collective magnetization dynamics in a synthetic antiferromagnet (SAF) nanoparticle and uncover a regime of barrier-free switching under a short small-amplitude magnetic field pulse applied perpendicular to the SAF plane. We give examples of specific implementations for forming such low-power and ultra-fast switching pulses. For fully optical, resonant, barrier-free SAF switching we estimate the power per write operation to be  pJ, 10-100 times smaller than for conventional quasi-static rotation, which should be attractive for memory applications.

Effect of Thermal Processing on the Structural and Magnetic Properties of Epitaxial CoFeGe Films.

The structure and magnetic properties of epitaxial Heusler alloy films (CoFeGe) deposited on MgO (100) substrates were investigated. Films of 60 nm thickness were prepared by magnetron co-sputtering at different substrate temperatures (T), and those deposited at room temperature were later annealed at various temperatures (T). X-ray diffraction confirmed (001) [110] CoFeGe || (001) [100] MgO epitaxial growth.

Proximity-enhanced magnetocaloric effect in ferromagnetic trilayers.

The demagnetization and associated magnetocaloric effect (MCE) in strong-weak-strong ferromagnetic trilayers, upon a reorientation of the strong ferromagnets from parallel to antiparallel (AP) magnetization, is simulated using atomistic spin dynamics. The simulations yield non-trivial spin distributions in the AP state, which in turn allows entropy to be calculated directly. The influence of longer-range spin-spin interactions and of variable strength of the external switching field are investigated.

Thermal Gating of Magnon Exchange in Magnetic Multilayers with Antiferromagnetic Spacers.

We observe a strong thermally controlled magnon-mediated interlayer coupling of two ferromagnetic layers via an antiferromagnetic spacer in spin-valve type trilayers. The effect manifests itself as a coherent switching as well as collective resonant precession of the two ferromagnets, which can be controlled by varying temperature and the spacer thickness. We explain the observed behavior as due to a strong hybridization of the ferro- and antiferromagnetic magnon modes in the trilayer at temperatures just below the Néel temperature of the antiferromagnetic spacer.

Angle Resolved Relaxation of Spin Currents by Antiferromagnets in Spin Valves.

We observe and analyze tunable relaxation of a pure spin current by an antiferromagnet in spin valves. This is achieved by carefully controlling the angle between a resonantly excited ferromagnetic layer pumping the spin current and the Néel vector of the antiferromagnetic layer. The effect is observed as an angle-dependent spin-pumping contribution to the ferromagnetic resonance linewidth.