Magnetic phase contrast

Finally, the array of modern LMs, including nuclear magnetic resonance, confocal laser, dark-field, phase-contrast fluorescence (Chapter 1), continues to be extended. The array offers the electron microsco-pist many opportunities for correlative LM and EM possibilities. 

Liu Y, Karonen JO, Vanninen RL et al. (2004) Acute ischemic stroke predictive value of 2D phase-contrast MR angiography-serial study with combined diffusion and perfusion MR imaging. Radiology 231 517-527 Lucas C, Leclerc X, Pruvo JP et al. (2000) [Vertebral artery dissections follow-up with magnetic resonance angiography and injection of gadolinium]. Rev Neurol (Paris) 156 1096-1105... 

But rather than considering spatially-dependent spectral properties, which often are essential for image contrast, time-dependent gradients shall be admitted to illustrate the basic concepts of space encoding. Then the space-dependent magnetization phase - yGrf in the exponent of the integrand has to be replaced by... 

By increasing the sample temperature both peaks of the Tb(OOOl) surface state shift towards thereby decreasing the exchange splitting A ex- Just above Tcb (T — 223 K) the occupied part of the surface state has already approached the Fermi level very closely [U — —50 34 mV]. In contrast to earlier experiments on Gd(OOOl), this trend continues for Tb(OOOl) even above its bulk magnetic phase transition temperatures Tcb = 220 K and Tnb = 228 K. At T = 248 K the former occupied part of the surface state is energetically localized at the Fermi level [17 = 10 30 mV]. Increasing the temperature further T — 258 K and T — 271 K) the maximum in the dUdU spectra crosses Ejs. As a result the surface state which was clearly occupied at low temperature (T = 85 K) becomes partially empty above T = 250 K. 

---