3 research outputs found
Flux Qubits with Long Coherence Times for Hybrid Quantum Circuits
We present measurements of superconducting flux qubits embedded in a three
dimensional copper cavity. The qubits are fabricated on a sapphire substrate
and are measured by coupling them inductively to an on-chip superconducting
resonator located in the middle of the cavity. At their flux-insensitive point,
all measured qubits reach an intrinsic energy relaxation time in the 6-20
microseconds range and a pure dephasing time comprised between 3 and 10
microseconds. This significant improvement over previous works opens the way to
the coherent coupling of a flux-qubit to individual spins
Leveraging nMOS Negative Differential Resistance for Low Power, High Reliability Magnetic Memory
International audienc
Giant interfacial perpendicular magnetic anisotropy in MgO/CoFe/capping layer structures
Magnetic tunnel junction (MTJ) based on CoFeB/MgO/CoFeB structures is of
great interest due to its application in the spin-transfer-torque magnetic
random access memory (STT-MRAM). Large interfacial perpendicular magnetic
anisotropy (PMA) is required to achieve high thermal stability. Here we use
first-principles calculations to investigate the magnetic anisotropy energy
(MAE) of MgO/CoFe/capping layer structures, where the capping materials include
5d metals Hf, Ta, Re, Os, Ir, Pt, Au and 6p metals Tl, Pb, Bi. We demonstrate
that it is feasible to enhance PMA by using proper capping materials.
Relatively large PMA is found in the structures with capping materials of Hf,
Ta, Os, Ir and Pb. More importantly, the MgO/CoFe/Bi structure gives rise to
giant PMA (6.09 mJ/m2), which is about three times larger than that of the
MgO/CoFe/Ta structure. The origin of the MAE is elucidated by examining the
contributions to MAE from each atomic layer and orbital. These findings provide
a comprehensive understanding of the PMA and point towards the possibility to
achieve advanced-node STT-MRAM with high thermal stability.Comment: 15 pages with 4 figure