Tuning the magnetic properties of self-assembled metal-phthalocyanine on intercalated graphene

We report on advanced organic spin-interface architectures constituted by metal (manganese, iron, copper) phthalocyanine molecules magnetically coupled with ferromagnetic layer(s), mediated by graphene. The rippled moiré superstructure of graphene/Ir(111), intercalated with a single magnetic layer, drives the assembly of evenly-spaced molecular bits, providing preferential adsorption regions for the phthalocyanine molecules. Our X-ray absorption and photoemission results show that the graphene layer shields the electronic/magnetic state of the molecules, screening the charge transfer/orbital intermixing with the metallic surface. The magnetic response of the molecular spin interfaces and its robustness against thermal fluctuations were investigated by X-ray magnetic circular dichroism. Mn-, Fe- and Cu-phthalocyanines assemble on graphene/Co with identical structural configurations, but MnPc and FePc are strongly antiferromagnetically coupled with Co up to room temperature, while CuPc couples ferromagnetically with weaker thermal stability. The robust antiferromagnetic alignment is stabilized by a superexchange interaction, driven by the out-of-plane molecular orbitals responsible of the magnetic ground state and electronically decoupled from the underlying metal via the graphene layer, as confirmed by ab initio theoretical predictions. The strength and stability of the magnetic coupling is further optimized by the open 3d shell of the central Mn ion. These archetypal spin interfaces can be prototypes to demonstrate how antiferromagnetic/ ferromagnetic coupling can be optimized by selecting the molecular orbital symmetry, paradigmatic examples to exploit in surface-supported molecular spin electronics

Tuning the magnetic coupling of a molecular spin interface via electron doping

Mastering the magnetic response of molecular spin interfaces by tuning the occupancy of the molecular orbitals, which carry the spin magnetic moment, can be accomplished by electron doping. We propose a viable route to control the magnetization direction and magnitude of a molecular spin network, in a graphene-mediated architecture, achieved via alkali doping of manganese phthalocyanine (MnPc) molecules assembled on cobalt intercalated under a graphene membrane. The antiparallel magnetic alignment of the MnPc molecules with the underlying Co layer can be switched to a ferromagnetic state by electron doping. Multiplet calculations unveil an enhanced magnetic state of the Mn centers with a 3/2 to 5/2 spin transition induced by alkali doping, as confirmed by the steepening of the hysteresis loops, with higher saturation magnetization values. This new molecular spin configuration can be aligned by an external field, almost independently from the hard-magnet substrate effectively behaving as a free magnetic layer

Magnetic response and electronic states of well defined Graphene/Fe/Ir(111) heterostructure

We investigate a well defined heterostructure constituted by magnetic Fe layers sandwiched between graphene (Gr) and Ir(111). The challenging task to avoid Fe-C solubility and Fe-Ir intermixing has been achieved with atomic controlled Fe intercalation at moderate temperature below 500 K. Upon intercalation of a single ordered Fe layer in registry with the Ir substrate, an intermixing of the Gr bands and Fe d states breaks the symmetry of the Dirac cone, with a downshift in energy of the apex by about 3 eV, and well-localized Fe intermixed states induced in the energy region just below the Fermi level. First principles electronic structure calculations show a large spin splitting of the Fe states, resulting in a majority spin channel almost fully occupied and strongly hybridized with Gr π states. X-ray magnetic circular dichroism on the Gr/Fe/Ir heterostructure reveals an ordered spin configuration with a ferromagnetic response of Fe layer(s), with enhanced spin and orbital configurations with respect to the bcc-Fe bulk values. The magnetization switches from a perpendicular easy magnetization axis when the Fe single layer is lattice matched with the Ir(111) surface to a parallel one when the Fe thin film is almost commensurate with graphene

Narrowing of d bands of FeCo layers intercalated under graphene

We report on the electronic properties of an artificial system obtained by the intercalation of equiatomic FeCo layers under graphene grown on Ir(111). Upon intercalation, the FeCo film grows epitaxially on Ir(111), resulting in a lattice-mismatched system. By performing density functional theory calculations, we show that the intercalated FeCo layer leads to a pronounced corrugation of the graphene film. At the same time, the FeCo intercalated layers induce a clear transition from a nearly undisturbed to a strongly hybridized graphene π-band, as measured by angle-resolved photoemission spectroscopy. A comparison of experimental results with the computed band structure and the projected density of states unveils a spin-selective hybridization between the π band of graphene and FeCo-3d states. Our results demonstrate that the reduced dimensionality, as well as the hybridization within the FeCo layers, induces a narrowing and a clear splitting of Fe 3d-up and Fe 3d-down-spin bands of the confined FeCo layers with respect to bulk Fe and Co

Empty electron states in cobalt-intercalated graphene

The dispersion of the electronic states of epitaxial graphene (Gr) depends significantly on the strength of the bonding with the underlying substrate. We report on empty electron states in cobalt-intercalated Gr grown on Ir(111), studied by angle-resolved inverse photoemission spectroscopy and x-ray absorption spectroscopy, complemented with density functional theory calculations. The weakly bonded Gr on Ir preserves the peculiar spectroscopic features of the Gr band structure, and the empty spectral densities are almost unperturbed. Upon intercalation of a Co layer, the electronic response of the interface changes, with an intermixing of the Gr π* bands and Co d states, which breaks the symmetry of π/σ states, and a downshift of the upper part of the Gr Dirac cone. Similarly, the image potential of Ir(111) is unaltered by the Gr layer, while a downward shift is induced upon Co intercalation, as unveiled by the image state energy dispersion mapped in a large region of the surface Brillouin zone

FePc Adsorption on the Moir\'e Superstructure of Graphene Intercalated with a Co Layer

The moir\'e superstructure of graphene grown on metals can drive the assembly of molecular architectures, as iron-phthalocyanine (FePc) molecules, allowing for the production of artificial molecular configurations. A detailed analysis of the Gr/Co interaction upon intercalation (including a modelling of the resulting moir\'e pattern) is performed here by density functional theory, which provides an accurate description of the template as a function of the corrugation parameters. The theoretical results are a preliminary step to describe the interaction process of the FePc molecules adsorption on the Gr/Co system. Core level photoemission and absorption spectroscopies have been employed to control the preferential adsorption regions of the FePc on the graphene moir\'e superstructure and the interaction of the central Fe ion with the underlying Co. Our results show that upon molecular adsorption the distance of C atoms from the Co template mainly drives the strength of the molecules-substrate interaction, thereby allowing for locally different electronic properties within the corrugated interface.Comment: This document is the Accepted Manuscript version of a Published Work that appeared in final form in J. Phys. Chem. C , copyright \c{opyright} American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/acs.jpcc.6b0987

A fast synthesis route of boron-carbon-nitrogen ultrathin layers towards highly mixed ternary B-C-N phases

We report a direct and fast synthesis route to grow boron-carbon-nitrogen layers based on microwave-assisted plasma enhanced chemical vapour deposition (PECVD) by using methylamine borane as a single source molecular precursor. This easy and inexpensive method allows controlled and reproducible growth of B-C-N layers onto thin Cu foils. Their morphological, structural, chemical, optical and transport properties have been thoroughly characterized by a number of different microscopies, transport and spectroscopic techniques. Though disorder and segregation into C-rich and h-BN-rich domains have been observed in ultrathin flat few layers, high doping levels have been reached, inducing strong modifications of the electronic, optical and transport properties of C-rich and h-BN-rich phases. This synthesis procedure can open new routes towards the achievement of homogeneous highly mixed ternary B-C-N phase

Multiple Myeloma Treatment in Real-world Clinical Practice : Results of a Prospective, Multinational, Noninterventional Study

Funding Information: The authors would like to thank all patients and their families and all the EMMOS investigators for their valuable contributions to the study. The authors would like to acknowledge Robert Olie for his significant contribution to the EMMOS study. Writing support during the development of our report was provided by Laura Mulcahy and Catherine Crookes of FireKite, an Ashfield company, a part of UDG Healthcare plc, which was funded by Millennium Pharmaceuticals, Inc, and Janssen Global Services, LLC. The EMMOS study was supported by research funding from Janssen Pharmaceutical NV and Millennium Pharmaceuticals, Inc. Funding Information: The authors would like to thank all patients and their families and all the EMMOS investigators for their valuable contributions to the study. The authors would like to acknowledge Robert Olie for his significant contribution to the EMMOS study. Writing support during the development of our report was provided by Laura Mulcahy and Catherine Crookes of FireKite, an Ashfield company, a part of UDG Healthcare plc, which was funded by Millennium Pharmaceuticals, Inc, and Janssen Global Services, LLC. The EMMOS study was supported by research funding from Janssen Pharmaceutical NV and Millennium Pharmaceuticals, Inc. Funding Information: M.M. has received personal fees from Janssen, Celgene, Amgen, Bristol-Myers Squibb, Sanofi, Novartis, and Takeda and grants from Janssen and Sanofi during the conduct of the study. E.T. has received grants from Janssen and personal fees from Janssen and Takeda during the conduct of the study, and grants from Amgen, Celgene/Genesis, personal fees from Amgen, Celgene/Genesis, Bristol-Myers Squibb, Novartis, and Glaxo-Smith Kline outside the submitted work. M.V.M. has received personal fees from Janssen, Celgene, Amgen, and Takeda outside the submitted work. M.C. reports honoraria from Janssen, outside the submitted work. M. B. reports grants from Janssen Cilag during the conduct of the study. M.D. has received honoraria for participation on advisory boards for Janssen, Celgene, Takeda, Amgen, and Novartis. H.S. has received honoraria from Janssen-Cilag, Celgene, Amgen, Bristol-Myers Squibb, Novartis, and Takeda outside the submitted work. V.P. reports personal fees from Janssen during the conduct of the study and grants, personal fees, and nonfinancial support from Amgen, grants and personal fees from Sanofi, and personal fees from Takeda outside the submitted work. W.W. has received personal fees and grants from Amgen, Celgene, Novartis, Roche, Takeda, Gilead, and Janssen and nonfinancial support from Roche outside the submitted work. J.S. reports grants and nonfinancial support from Janssen Pharmaceutical during the conduct of the study. V.L. reports funding from Janssen Global Services LLC during the conduct of the study and study support from Janssen-Cilag and Pharmion outside the submitted work. A.P. reports employment and shareholding of Janssen (Johnson & Johnson) during the conduct of the study. C.C. reports employment at Janssen-Cilag during the conduct of the study. C.F. reports employment at Janssen Research and Development during the conduct of the study. F.T.B. reports employment at Janssen-Cilag during the conduct of the study. The remaining authors have stated that they have no conflicts of interest. Publisher Copyright: © 2018 The AuthorsMultiple myeloma (MM) remains an incurable disease, with little information available on its management in real-world clinical practice. The results of the present prospective, noninterventional observational study revealed great diversity in the treatment regimens used to treat MM. Our results also provide data to inform health economic, pharmacoepidemiologic, and outcomes research, providing a framework for the design of protocols to improve the outcomes of patients with MM. Background: The present prospective, multinational, noninterventional study aimed to document and describe real-world treatment regimens and disease progression in multiple myeloma (MM) patients. Patients and Methods: Adult patients initiating any new MM therapy from October 2010 to October 2012 were eligible. A multistage patient/site recruitment model was applied to minimize the selection bias; enrollment was stratified by country, region, and practice type. The patient medical and disease features, treatment history, and remission status were recorded at baseline, and prospective data on treatment, efficacy, and safety were collected electronically every 3 months. Results: A total of 2358 patients were enrolled. Of these patients, 775 and 1583 did and did not undergo stem cell transplantation (SCT) at any time during treatment, respectively. Of the patients in the SCT and non-SCT groups, 49%, 21%, 14%, and 15% and 57%, 20%, 12% and 10% were enrolled at treatment line 1, 2, 3, and ≥ 4, respectively. In the SCT and non-SCT groups, 45% and 54% of the patients had received bortezomib-based therapy without thalidomide/lenalidomide, 12% and 18% had received thalidomide/lenalidomide-based therapy without bortezomib, and 30% and 4% had received bortezomib plus thalidomide/lenalidomide-based therapy as frontline treatment, respectively. The corresponding proportions of SCT and non-SCT patients in lines 2, 3, and ≥ 4 were 45% and 37%, 30% and 37%, and 12% and 3%, 33% and 27%, 35% and 32%, and 8% and 2%, and 27% and 27%, 27% and 23%, and 6% and 4%, respectively. In the SCT and non-SCT patients, the overall response rate was 86% to 97% and 64% to 85% in line 1, 74% to 78% and 59% to 68% in line 2, 55% to 83% and 48% to 60% in line 3, and 49% to 65% and 36% and 45% in line 4, respectively, for regimens that included bortezomib and/or thalidomide/lenalidomide. Conclusion: The results of our prospective study have revealed great diversity in the treatment regimens used to manage MM in real-life practice. This diversity was linked to factors such as novel agent accessibility and evolving treatment recommendations. Our results provide insight into associated clinical benefits.publishersversionPeer reviewe

High thermal stability of anti-ferromagnetic coupled molecules with FeCo layers

We propose the optimization of the magnetic remanence and the thermal stability of Mn phthalocyanine coupled with a ferromagnetic substrate, by exploiting interlayer exchange coupling within an advanced organic spin interface architecture, constituted by a FeCo film covered by a graphene membrane, hosting the MnPc molecular layer. The challenge to obtain magnetic remanence for molecular systems stable up to room temperature has been accomplished thanks to a super-exchange path, mediated by the π orbital of the organic ligands of the molecule and of the graphene sheet, favoring an antiferromagnetic (AFM) alignment for the MnPc molecules with the FeCo film. This spin interface with a strong AFM coupling mediated by a graphene spacer is optimized against thermal fluctuations, presenting a well defined remanence even at room temperature, as demonstrated by the persistent dichroic signal in temperature-dependent circularly polarized x-ray absorption spectra

Graphene-mediated interaction between FePc and intercalated cobalt layers

The interaction strength of FePc molecules adsorbed on graphene-Co, obtained by intercalation of Co layer(s) under graphene (Gr) grown on Ir(111), has been investigated by core level photoemission and X-ray absorption spectroscopy. Upon intercalation of a single layer of Co beneath Gr, the Co atoms are pseudomorphic with the Ir(111) lattice, inducing a rippled Gr layer with valley and hill regions. FePc molecules, adsorbed on Gr/1 ML Co, are trapped in the valley regions and the Fe metallic centers strongly interact with the Gr/Co system. The intercalation of further Co layers leads to a relaxation of the Co lattice up to the formation of a commensurate (1 × 1) Gr/Co system. The Fe centers of the molecules adsorbed on the flat commensurate Gr/Co are found to be less interacting. We have determined that, even though the organic macrocycles of the FePc molecules, flat lying on the Gr/Co system, are completely decoupled by the presence of the Gr intralayer, the Fe–Co interaction is mediated by the graphene spacer and dependent on Gr corrugation