Local Magnetic Properties of a Monolayer of Mn₁₂ Single Molecule Magnets

Abstract

The magnetic properties of a monolayer of Mn12 single molecule magnets grafted onto a silicon (Si) substrate have been investigated using depth-controlled beta-detected nuclear magnetic resonance. A low-energy beam of spin-polarized radioactive 8Li was used to probe the local static magnetic field distribution near the Mn12 monolayer in the Si substrate. The resonance line width varies strongly as a function of implantation depth as a result of the magnetic dipolar fields generated by the Mn12 electronic magnetic moments. The temperature dependence of the line width indicates that the magnetic properties of the Mn12 moments in this low-dimensional configuration differ from bulk Mn12.

Proximal magnetometry in thin films using NMR

“…The main purpose of this section is to obtain k c . The implantation depth of both bNMR and LElSR is variable between a few nanometers and a few hundred nm, while the typical beamspot for 8 Li þ is about 3 mm diameter and somewhat larger for the low energy l þ . A typical film dimension for bNMR is 8 mm by 10 mm by 100 nm thick, with the beam centred on this area.…”

“…For these reasons, it is interesting to consider what information might be obtained by ''implanted ion proximal magnetometry'' (IIPM). We note several experiments along these lines have already been accomplished using bNMR [4,[8][9][10], and that IIPM is similar to NMR and EPR decoration experiments (the analogue of Bitter decoration of a superconductor) [11] and the use of adsorbed layers of hyperpolarized 129 Xe [12], but with the advantage of an easily controlled probe depth and a thin film geometry. We discuss this application in Section 4 and illustrate the results with experimental data in Section 5.…”

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

“…Recently, molecular junctions based on single-molecule magnets ͑SMMs͒ connected to electrodes or monolayers of SMMs at surfaces, have been fabricated and their electron-transport characteristics [1][2][3][4][5][6] have been measured, as well as their mechanical, electronic, and magnetic properties. [7][8][9][10][11][12][13] Electron transport through an SMM drew a lot of attention because of the intriguing interplay between its transport properties and the internal magnetic degrees of freedom, which is absent in transport through small organic molecules. An SMM consists of several transition metal ions interacting through organic or inorganic ligands via superexchange interactions.…”

First-principles study of a single-molecule magnetMn12monolayer on the Au(111) surface

“…4 These properties of SMMs propelled interest in utilizing SMMs as information storage devices, 5 spin-based devices, 6 or materials for quantum computation. 7 A great amount of experiments were carried out on deposition of SMMs Mn 12 or its derivatives on gold [8][9][10][11] and silicon [12][13][14] surfaces or on bridging them between gold electrodes. [15][16][17] Among thousands of synthesized SMMs, ͓Mn 12 O 12 ͑CH 3 COO͒ 16 ͑H 2 O͒ 4 ͔ ͑referred to as Mn 12 ͒ was widely studied due to its large magnetic anisotropy barrier ͑MAB͒ or magnetization reversal barrier of 65 K. 18 Largely, Mn 12 molecules were deposited onto a surface or bridged between electrodes in two different manners: ͑i͒ Through attractive van der Waals forces between the surface and Mn 12 without surface-binding ligands or ͑ii͒ via ligand exchange with the Mn 12 molecules.…”