Thermally assisted switching

Figure 19. MRAM cell for thermally assisted switching with one MTJ in series with a transistor. In this architecture the transistor must cope with the full write/heat current, but a single word line is required.

Figure 20. Example of double barrier magnetic tunnel junctions used in thermally assisted switching double free layer and weakly pinned storage layer (left) and minor TMR loops of double barriers junctions (right). Solid squares prior to pulse heating, open triangles after heating pulse and reversing the pinned layer in a 60 Oe easy axis external field. The junction area is 1 pm2, and a TMR of 25% and a resistance x area product of300 Opm2 are obtained.

Acknowledgement We thank the Ministerio Espanol de Ciencia y Tecnologfa (project BQU 2001-2928) for financial assistance. We also thank the European Commission for granting the TMR-Network Thermal and Optical Switching of Molecular Spin States... 

Although a UV laser is commonly used to des-orb/ionise matrix species in the vacuum of the mass spectrometer also IR lasers may be employed in the desorption process. IR MALDI normally uses tuneable IR (from 1.5 to 4.0 /rm), Q-switched Er-YAG (2.94 /rm, t = 90 ns) or Er-YSGG (2.79 /rm, r = 90 ns) lasers. Smaller absorption coefficients of usable matrices in IR as compared to UV result in an at least tenfold increase in ablated material per laser exposure. With IR lasers localised thermal desorption or laser assisted pyrolysis occurs. The desorbed neutrals expand into a small ionisation chamber where they may be post-ionised by electron impact or photoionisation. The dependence of... 

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