{"id":33337,"date":"2018-03-09T09:30:25","date_gmt":"2018-03-09T09:30:25","guid":{"rendered":"https:\/\/www.deberes.net\/tesis\/sin-categoria\/estudio-experimental-del-efecto-tunel-cuantico-en-materiales-magneticos\/"},"modified":"2018-03-09T09:30:25","modified_gmt":"2018-03-09T09:30:25","slug":"estudio-experimental-del-efecto-tunel-cuantico-en-materiales-magneticos","status":"publish","type":"post","link":"https:\/\/www.deberes.net\/tesis\/fisica\/estudio-experimental-del-efecto-tunel-cuantico-en-materiales-magneticos\/","title":{"rendered":"Estudio experimental del efecto tunel cuantico en materiales magneticos."},"content":{"rendered":"<h2>Tesis doctoral de <strong> Fernando Mar\u00eda Luis Vitalla <\/strong><\/h2>\n<p>Existen muy pocos ejemplos experimentales que revelen la existencia de fen]omenos cu\u00e1nticos a escala macrosc]opica. Este trabajo de tesis ha contribuido al estudio de dichos fen]omenos en diversos materiales magn\u00e9ticos.  se ha implementado una instalaci]on de medida de la susceptibilidad magn\u00e9tica alterna por debajo de 1 k sobre un refrigerador de diluci]on comercial. Los datos de susceptibilidad han permitido establecer que el ndga03 se ordena antiferomagn\u00e9ticamente (estructura cz) a t=1k y se han interpretado con un modelo de ising. Hemos establecido que la susceptibilidad magn\u00e9tica alterna permite obtener la distribuci]on de tama\u00f1os de part\u00edcula de una muestra de part\u00edculas monodominio y distinguir entre relajaci]on cl\u00e1sica (activada t\u00e9rmicamente) y el efecto t\u00fanel de los momentos magn\u00e9ticos. Hemos determinado experimentalmente con este m\u00e9todo la distribuci]on de tama\u00f1os de una muestra de part\u00edculas de cofe204 y de ferritina natural. En ambos casos se ha estudiado el efecto de la interacci]on sobre la relajaci]on magn\u00e9tica de las part\u00edculas y la contribuci]on de los espines superficiales. La susceptibilidad magn\u00e9tica no muestra evidencia alguna de efecto t\u00fanel en estos materiales. Nuestros datos son compatibles con la existencia de efecto t\u00fanel resonante por estados excitados en la ferritina. El acetato de mn12 tiene un \u00fanico tiempo de relajaci]on magn\u00e9tico que hemos determinado experimentalmente a partir de la susceptibilidad magn\u00e9tica. En contra de las predicciones clasicas, el tiempo de relajaci]on es m\u00ednimo a los campos en que existe degeneraci]on entre algunos niveles de esp\u00edn opuesto. Estos datos muestran que existe efecto t\u00fanel entre dichos estados, activados t\u00e9rmicamente. Hemos elaborado una teor\u00eda que da cuenta, cuantitativamente, de los resultados en acetato de mn12. Hemos establecido que el mecanismo de relajaci]on es incoherente, a pesar de que el efecto t\u00fanel influye decisivamente, y p<\/p>\n<p>&nbsp;<\/p>\n<h3>Datos acad\u00e9micos de la tesis doctoral \u00ab<strong>Estudio experimental del efecto tunel cuantico en materiales magneticos.<\/strong>\u00ab<\/h3>\n<ul>\n<li><strong>T\u00edtulo de la tesis:<\/strong>\u00a0 Estudio experimental del efecto tunel cuantico en materiales magneticos. <\/li>\n<li><strong>Autor:<\/strong>\u00a0 Fernando Mar\u00eda Luis Vitalla <\/li>\n<li><strong>Universidad:<\/strong>\u00a0 Zaragoza<\/li>\n<li><strong>Fecha de lectura de la tesis:<\/strong>\u00a0 24\/11\/1997<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3>Direcci\u00f3n y tribunal<\/h3>\n<ul>\n<li><strong>Director de la tesis<\/strong>\n<ul>\n<li>Juan Bartolom\u00e9 Sanjoaquin<\/li>\n<\/ul>\n<\/li>\n<li><strong>Tribunal<\/strong>\n<ul>\n<li>Presidente del tribunal: joaquin Marro <\/li>\n<li>jos De jongh (vocal)<\/li>\n<li>Javier Tejada palacios (vocal)<\/li>\n<li>pablo j. Alonso gasc\u00f3n (vocal)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tesis doctoral de Fernando Mar\u00eda Luis Vitalla Existen muy pocos ejemplos experimentales que revelen la existencia de fen]omenos cu\u00e1nticos a [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[199,1008,1007,28867,13610],"tags":[91025,19129,91026,91027,14622,91028],"class_list":["post-33337","post","type-post","status-publish","format-standard","hentry","category-fisica","category-fisica-del-estado-solido","category-propiedades-magneticas-de-los-solidos","category-resonancia-magnetica","category-zaragoza","tag-fernando-maria-luis-vitalla","tag-javier-tejada-palacios","tag-joaquin-marro","tag-jos-de-jongh","tag-juan-bartolome-sanjoaquin","tag-pablo-j-alonso-gascon"],"_links":{"self":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/33337","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/comments?post=33337"}],"version-history":[{"count":0,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/posts\/33337\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/media?parent=33337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/categories?post=33337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.deberes.net\/tesis\/wp-json\/wp\/v2\/tags?post=33337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}