{"id":1259,"date":"2010-07-02T12:15:07","date_gmt":"2010-07-02T16:15:07","guid":{"rendered":"https:\/\/wpmu2.mit.local\/?p=1259"},"modified":"2010-07-02T12:15:07","modified_gmt":"2010-07-02T16:15:07","slug":"josephson-junction-development-in-superconducting-all-mgb2-thin-film-vertical-and-lateral-junctions","status":"publish","type":"post","link":"https:\/\/wpmu2.mit.local\/josephson-junction-development-in-superconducting-all-mgb2-thin-film-vertical-and-lateral-junctions\/","title":{"rendered":"Josephson Junction Development in Superconducting All-MgB<sub>2<\/sub> Thin-film Vertical and Lateral Junctions"},"content":{"rendered":"<div class=\"page-restrict-output\"><div id=\"attachment_1261\" class=\"wp-caption alignright\" style=\"width: 310px;\"><a rel=\"lightbox[1259]\" href=\"https:\/\/wpmu2.mit.local\/files\/2010\/07\/Laloe-MgB2-figure1-e1278087225529.jpg\"><img loading=\"lazy\" class=\"size-medium wp-image-1261\" title=\"Figure 1\" src=\"https:\/\/wpmu2.mit.local\/files\/2010\/07\/Laloe-MgB2-figure1-300x225.jpg\" alt=\"Figure 1\" width=\"300\" height=\"225\" \/><\/a><\/p>\n<p class=\"wp-caption-text\">Figure 1: Electron microscope image of the weak-link region in a MgB<sub>2<\/sub> thin film lateral device. The proximity of the Fe in the bilayer region of Fe\/MgB<sub>2<\/sub> causes local weakening or complete suppression of superconductivity, depending on the thickness of the MgB<sub>2<\/sub> thin film.<\/p>\n<\/div>\n<p>MgB<sub>2<\/sub> is a multi-gap superconductor with a <em>T<sub>C<\/sub><\/em> of 39K and a hexagonal structure. This simple and stable compound is very attractive for device applications. We have developed thin-film all-MgB<sub>2<\/sub> devices, both in the vertical geometry with a sputtered MgO barrier, and in the lateral geometry by creating weak-link junctions using proximity with Fe. In the first case, we have deposited and patterned micron-sized SIS tunnel junctions with highly textured MgB<sub>2<\/sub> electrodes grown by MBE co-evaporation with sputter-deposited MgO tunnel barriers, in an entirely in-situ process. This method enabled us to obtain low-resistance junctions with very good oxide coverage. The I-V and dI\/dV data display Josephson pair tunneling as well as the quasi-particle tunneling signature of both the Pi- and Sigma-bands of the MgB<sub>2<\/sub>, with gap values agreeing with previous reports. Although our MgB<sub>2<\/sub> films were c-axis oriented, the growth-related roughness of the bottom MgB<sub>2<\/sub> enabled a\/b-axis tunneling, giving rise to Sigma-band features. The layers for lateral junctions were also deposited entirely in situ, the Fe film directly in contact with the MgB<sub>2<\/sub> film, and these films were subsequently patterned into lateral bars. This configuration creates <em>S1\/U\/S1<\/em> junctions, where <em>U<\/em> is the Fe\/MgB<sub>2<\/sub> bilayer region, and is either a weakened superconductor <em>S2<\/em>, or a normal metal <em>N<\/em> in the case where superconductivity is completely suppressed in the MgB<sub>2<\/sub> thin film. Figure 1 is an electron microscope image of the weak link region in one of our typical devices. Current transport in these junctions is in the plane of the film, along the a\/b-axis of the superconductor. We observe signs of pair tunneling through the weakened region.<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"<div class=\"page-restrict-output\"><p>Figure 1: Electron microscope image of the weak-link region in a MgB2 thin film lateral device. The proximity of the&#8230;<\/p>\n<\/div>","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[28,8],"tags":[4092,4133],"_links":{"self":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1259"}],"collection":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/comments?post=1259"}],"version-history":[{"count":5,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1259\/revisions"}],"predecessor-version":[{"id":1265,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1259\/revisions\/1265"}],"wp:attachment":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/media?parent=1259"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/categories?post=1259"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/tags?post=1259"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}