{"id":16401,"date":"2011-04-17T19:17:42","date_gmt":"2011-04-17T16:17:42","guid":{"rendered":"http:\/\/www.fyysika.ee\/uudised\/?p=16401"},"modified":"2011-04-17T19:17:42","modified_gmt":"2011-04-17T16:17:42","slug":"uued-avastused-grafeeni-magnetismi-alal","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=16401","title":{"rendered":"Uued avastused grafeeni magnetismi alal"},"content":{"rendered":"<p><strong>Marylandi \u00dclikooli teadlased avastasid viisi kuidas hoida kontrolli all grafeeni magnetilisi omadusi. Uus meetod v\u00f5ib viia uute rakendusteni magnetilises salvestuses ja magnetm\u00e4ludes.<\/strong><\/p>\n<div id=\"attachment_16402\" style=\"width: 236px\" class=\"wp-caption alignleft\"><a href=\"http:\/\/www.fyysika.ee\/uudised\/wp-content\/uploads\/2011\/04\/scientistsma.gif\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-16402\" class=\"size-medium wp-image-16402\" title=\"scientistsma\" src=\"http:\/\/www.fyysika.ee\/uudised\/wp-content\/uploads\/2011\/04\/scientistsma-226x300.gif\" alt=\"\" width=\"226\" height=\"300\" srcset=\"https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/04\/scientistsma-226x300.gif 226w, https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/04\/scientistsma-773x1024.gif 773w, https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/04\/scientistsma-250x331.gif 250w, https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/04\/scientistsma.gif 1083w\" sizes=\"auto, (max-width: 226px) 100vw, 226px\" \/><\/a><p id=\"caption-attachment-16402\" class=\"wp-caption-text\">Skeem grafeentransistorist, millel on n\u00e4idatud grafeen(punane), kuldelektroodid(kollane), r\u00e4nidioksiid(l\u00e4bipaistev) ning r\u00e4nisubstraat(must). Suurendatult on toodud grafeenv\u00f5restik, milles on &quot;augud.&quot; &quot;Augud(puuduvad aatomid)&quot; on pildil \u00fcmbritsetud siniste s\u00fcsinikuaatomitega.<\/p><\/div>\n<p>Oma uurimust\u00f6\u00f6s leidsid teadlased, et grafeeni puuduvad aatomid ehk nn &#8220;augud&#8221; k\u00e4ituvad kui v\u00e4ikesed magnetid &#8211; neil on magnetmoment. Lisaks astuvad need magnetmomendid tugevalt vastasm\u00f5jusse grafeenis voolu kandvate elektronidega, p\u00f5hjustades madalal temperatuuril m\u00e4rgatava lisatakistuse &#8211; n\u00e4htus, mida tuntakse Knodo efekti nime all, kirjutab <a href=\"http:\/\/www.physorg.com\/news\/2011-04-scientists-magnetic-graphene-discovery.html\">Physorg.com<\/a>.<\/p>\n<p>Kondo efekti leidmine grafeenis oli \u00fcllatav kahel p\u00f5hjusel. &#8220;Esiteks, me uurisime ainult s\u00fcsinikust koosnevat s\u00fcsteemi lisamata tavalisi magnetilisi ebapuhtusi. Teiseks, grafeenil on v\u00e4ga v\u00e4ikene elektrontihedus, mist\u00f5ttu Kondo efekti ilmnemine peaks toimuma ainult v\u00e4ga madalatel temperatuuridel,&#8221; s\u00f5nas uurimuse l\u00e4bi viinud f\u00fc\u00fcsikaprofessor Michael S. Fuhrer.<\/p>\n<p>Teadlased m\u00f5\u00f5tsid &#8220;aukudega&#8221; grafeenis aset leidnud Kondo efekti karakteristlikuks temperatuuriks kuni 90 Kelvinit, mis on v\u00f5rreldav v\u00e4ga suurte elektrontihedustega metallide vastava temperatuuriga. Lisaks saab Kondo efekti temperatuuri elektripaisu pingega muuta &#8211; omadus, mis metallidel puudub. Nad teoretiseerisid, et samasugused ebatavalised omadused grafeeni elektronides, mis k\u00e4ituvad justkui neil puuduks mass, p\u00f5hjustab ka nende suurt vastastikm\u00f5ju kindlate ebapuhtustega(n\u00e4iteks &#8220;aukudega&#8221;), viies tugeva Kondo efekti tekkimiseni v\u00f5rdlemisi k\u00f5rgel temperatuuril.<\/p>\n<p>Fuhreri arvates saaks grafeeni &#8220;aukude&#8221; kindlal j\u00e4rjestamisel tekitada ferromagnetismi. ,,\u00dcksikud magnetmomendid saaks seostada Kondo efektiga, sundides neid k\u00f5iki samas suunas asetuma,&#8221; selgitas ta.<\/p>\n<p>,,Tulemuseks saadaks ferromagnet(nagu raud), mis koosneb ainult s\u00fcsinikust. Grafeeni magnetismi abil saaks luua uusi nanoskaalas sensoreid, mis t\u00f6\u00f6taksid magnetv\u00e4ljas(<a href=\"http:\/\/www.fyysika.ee\/uudised\/?p=16343\">Loe artiklit grafeenis avastatud magnetismist<\/a>). Samuti v\u00f5iks see viia nn defektit\u00f6\u00f6tluseni grafeenis &#8211; aatomite v\u00e4lja noppimine kindlatest kohtadest, saades nii soovitud magnetilised omadused,&#8221; s\u00f5nas Fuhrer.<\/p>\n<p><a href=\"http:\/\/www.physorg.com\/news\/2011-04-scientists-magnetic-graphene-discovery.html\">Allikas<\/a><\/p>\n<p>Teadusartikkel: &#8220;<a href=\"http:\/\/www.nature.com\/nphys\/journal\/vaop\/ncurrent\/full\/nphys1962.html\">Tunable Kondo effect in graphene with defects<\/a>&#8220;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Marylandi \u00dclikooli teadlased avastasid viisi kuidas hoida kontrolli all grafeeni magnetilisi omadusi. Uus meetod v\u00f5ib viia uute rakendusteni magnetilises salvestuses ja magnetm\u00e4ludes. Oma uurimust\u00f6\u00f6s leidsid teadlased, et grafeeni puuduvad aatomid ehk nn &#8220;augud&#8221; k\u00e4ituvad kui v\u00e4ikesed magnetid &#8211; neil on magnetmoment. Lisaks astuvad need magnetmomendid tugevalt vastasm\u00f5jusse grafeenis voolu kandvate elektronidega, p\u00f5hjustades madalal temperatuuril m\u00e4rgatava [&hellip;]<\/p>\n","protected":false},"author":32,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[31,16],"tags":[],"class_list":{"0":"post-16401","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rakenduslik-teadus","7":"category-teadusuudis","8":"entry","9":"has-post-thumbnail"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/16401","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/32"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=16401"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/16401\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16401"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16401"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16401"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}