The Complete Retirement Survival Guide : Everything You Need to Know to Safeguard Your Money, Your Health, and Your Independence

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An investigation into the feasibility of myoglobin-based single-electron transistors

Myoglobin single-electron transistors were investigated using nanometer- gap platinum electrodes fabricated by electromigration at cryogenic temperatures. Apomyoglobin (myoglobin without heme group) was used as a reference. The results suggest single electron transport is mediated by resonant tunneling with the electronic and vibrational levels of the heme group in a single protein. They also represent a proof-of-principle that proteins with redox centers across nanometer-gap electrodes can be utilized to fabricate single-electron transistors. The protein orientation and conformation may significantly affect the conductance of these devices. Future improvements in device reproducibility and yield will require control of these factors

Antiferromagnetic spin Seebeck Effect

We report on the observation of the spin Seebeck effect in antiferromagnetic MnF$_2$. A device scale on-chip heater is deposited on a bilayer of Pt (4 nm)/MnF$_2$ (110) (30 nm) grown by molecular beam epitaxy on a MgF$_2$ (110) substrate. Using Pt as a spin detector layer it is possible to measure thermally generated spin current from MnF$_2$ through the inverse spin Hall effect. The low temperature (2 - 80 K) and high magnetic field (up to 140 kOe) regime is explored. A clear spin flop transition corresponding to the sudden rotation of antiferromagnetic spins out of the easy axis is observed in the spin Seebeck signal when large magnetic fields (>9 T) are applied parallel the easy axis of the MnF$_2$ thin film. When magnetic field is applied perpendicular to the easy axis, the spin flop transition is absent, as expected

Ferrimagnetism of dilute Ising antiferromagnets

It is shown that nearest-neighbor antiferromagnetic interactions of identical Ising spins on imbalanced bipartite lattice and imbalanced bipartite hierarchical fractal result in ferrimagnetic order instead of antiferromagnetic one. On some crystal lattices dilute Ising antiferromagnets may also become ferrimagnets due to the imbalanced nature of the magnetic percolation cluster when it coexists with the percolation cluster of vacancies. As evidenced by the existing experiments on $Fe_pZn_{1-p}F_2$, such ferrimagnetism is inherent property of bcc lattice so thermodynamics of these compounds at low $p$ can be similar to that of antiferromagnet on imbalanced hierarchical fractal.Comment: 6 pages, 4 figure