Millennials Millennials Millennials, also known as Generation Y or Gen Y, are the generational demographic cohort following Generation X and preceding Generation Z. There are no precise dates for when this cohort starts or ends; demographers and researchers typically use the early 1980s as starting birth years and the mid-1990s to early 2000s as ending birth years. Millennials are sometimes referred to as "echo boomers" due to a major surge in birth rates in the 1980s and 1990s, and because millennials are often the children of the baby boomers. Although millennial characteristics vary by region, depending on social and economic conditions,
Spin echo laser spectroscopy and neutron scattering. Echoes were first detected in nuclear magnetic resonance by Erwin Hahn in 1950, and spin echoes are sometimes referred to as Hahn echoes. In nuclear magnetic resonance and magnetic resonance imaging, radiofrequency radiation is most commonly used. In 1972 F. Mezei introduced spin echo neutron scattering, a technique that can be used to study magnons and phonons in single crystals. The technique is now applied in research facilities using triple axis spectrometers. The spin echo effect was discovered by Erwin Hahn when he applied two successive 90° pulses separated by short time period, but detected