h1. {color:#000000}Two Paradigms of Magnetism{color} Magnetism is a macroscopic phenomenon with its origin deeply rooted in quantum mechanics. In condensed matter physics, there are two paradigms for magnetism: localized spins interacting via tunnelling, and delocalized spins interacting via an exchange energy. The latter gives rise to itinerant ferromagnetism which is responsible for the properties of transition metals like cobalt, iron and nickel. Both kinds of magnetism involve strong correlations and/or strong interactions and are not yet completely understood. For localized spins, major open questions include the interplay of magnetism with d-wave superfluidity and frustrated spin materials. For itinerant ferromagnetism, phase transition theories are still qualitative. h1. {color:#000000}What is needed for Itinerant Ferromagnetism?{color} !ferromagnetism.jpg|width=648,height=486! v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} p\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} v\:textbox {display:none;}Slide 20.O {color:black; font-size:149%;} a:link {color:#CCCCFF !important;} a:active {color:#3333CC !important;} a:visited {color:#B2B2B2 !important;}.sld {left:0px !important; width:6.0in !important; height:4.5in !important; font-size:103% !important;} • |