fabrication-of-spatially-confined-complex-oxides

Fabrication of Spatially Confined Complex Oxides

Complex materials such as high Tc superconductors, multiferroics, and colossal magnetoresistors have electronic and magnetic properties that arise from ...

Oak Ridge National Laboratory

Using in situ magneto-optical Kerr effect measurements and phenomenological modeling, we study the tunability in both the magnetization anisotropy and magnetic coupling of Fe nanodots on a curved Cu(111) substrate with varying vicinity. We observe that, as the terrace width w decreases, the magnetization anisotropy increases monotonically, faster when w is smaller than the nanodot size d. In contrast, the magnetic coupling strength also increases until w approximately d, after which it decreases steeply. These striking observations can be rationalized by invoking the counterintuitive dimensionality variation of the surface electrons mediating the interdot coupling: the electrons are confined to be one dimensional (1D) when w > or = d, but become quasi-2D when w < d due to enhanced electron spillover across the steps bridged by the nanodots.

Tuning the ferromagnetic coupling of Fe nanodots on Cu(111) via dimensionality variation of the mediating electrons.

&Agrave; l&#39;aide de mesures d&#39;effet Kerr magn&eacute;to-optique in situ et mod&eacute;lisation ph&eacute;nom&eacute;nologique, nous &eacute;tudions l&#39;accordabilit&eacute; dans l&#39;anisotropie de l&#39;aimantation et couplage magn&eacute;tique de Fe nanodots sur un substrat de courbes incurv&eacute; avec voisinage variable. Nous observons que, quand la terrasse largeur w baisse, l&#39;anisotropie de l&#39;aimantation augmente monotone, plus vite quand w est plus petit que la taille d &agrave; NANOPOINTS. En revanche, la force de couplage magn&eacute;tique augmente &eacute;galement jusqu&#39;&agrave; w environ d, apr&egrave;s quoi il diminue abruptement. Ces observations de substitution peuvent &ecirc;tre expliqu&eacute;es en invoquant la variation contre-intuitif dimensionnalit&eacute; des &eacute;lectrons surfaces m&eacute;diant l&#39;attelage interdot : les &eacute;lectrons sont confin&eacute;s pour &ecirc;tre unidimensionnelles (1D) o&ugrave; w &gt; ou = d, mais devenir quasi-2D quand w &lt; d en raison du d&eacute;bordement d&#39;&eacute;lectrons am&eacute;lior&eacute; &agrave; travers les &eacute;tapes combl&eacute; par la nanodots.

Le couplage ferromagn&eacute;tique de Fe nanodots sur respectivement par variation de la dimensionnalit&eacute; des &eacute;lectrons m&eacute;diatrices de l&#39;accordage.

Utilizzando in situ misure di effetto Kerr magneto-ottiche e modellizzazione fenomenologica, studiamo il sintonizzabilit&agrave; nella magnetizzazione anisotropia e accoppiamento magnetico di Fe nanodots su un substrato Cu(111) curvo con varie vicinanze. Osserviamo che, come la terrazza larghezza w diminuisce, l&#39;anisotropia di magnetizzazione aumenta monotonicamente, pi&ugrave; veloce quando w &egrave; minore la nanodot dimensione d. Al contrario, la forza di accoppiamento magnetico aumenta anche fino a w circa d, dopo di che diminuisce vertiginosamente. Questi colpisce le osservazioni possono essere razionalizzati richiamando la variazione controintuitivo dimensionalit&agrave; degli elettroni superficiali mediando l&#39;accoppiamento interdot: gli elettroni sono confinati per essere monodimensionale (1D) quando w &amp;gt; o = d, ma diventano quasi 2D quando w &lt; d a causa di spillover elettrone avanzata attraverso i passaggi colmato dal nanodots.

Thomas Z. Ward

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