Spin tuning of electron-doped metal-phthalocyanine layers
The spin state of organic-based magnets at interfaces is to a great extent determined by the organic environment and the nature of the spin-carrying metal center, which is further subject to modifications by the adsorbate-substrate coupling. Direct chemical doping offers an additional route for tail...
| Autores: | , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:232112 |
| Acceso en línea: | https://ddd.uab.cat/record/232112 https://dx.doi.org/urn:doi:10.1021/ja501204q |
| Access Level: | acceso abierto |
| Palabra clave: | Adsorbate-substrate Alkali metal doping Alkali-metal adsorption Magnetic characteristic Magnetic configuration Molecular magnet Orbital magnetic moment Organic-based magnets Circular dichroism Electrons Indoles Metals, Alkali Metals, Heavy Microscopy, Scanning Tunneling Organometallic Compounds X-Ray Absorption Spectroscopy |
| Sumario: | The spin state of organic-based magnets at interfaces is to a great extent determined by the organic environment and the nature of the spin-carrying metal center, which is further subject to modifications by the adsorbate-substrate coupling. Direct chemical doping offers an additional route for tailoring the electronic and magnetic characteristics of molecular magnets. Here we present a systematic investigation of the effects of alkali metal doping on the charge state and crystal field of 3d metal ions in Cu, Ni, Fe, and Mn phthalocyanine (Pc) monolayers adsorbed on Ag. Combined X-ray absorption spectroscopy and ligand field multiplet calculations show that Cu(II), Ni(II), and Fe(II) ions reduce to Cu(I), Ni(I), and Fe(I) upon alkali metal adsorption, whereas Mn maintains its formal oxidation state. The strength of the crystal field at the Ni, Fe, and Mn sites is strongly reduced upon doping. The combined effect of these changes is that the magnetic moment of high- and low-spin ions such as Cu and Ni can be entirely turned off or on, respectively, whereas the magnetic configuration of MnPc can be changed from intermediate (3/2) to high (5/2) spin. In the case of FePc a 10-fold increase of the orbital magnetic moment accompanies charge transfer and a transition to a high-spin state. |
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