Spin orientation in solid solution hematite-ilmenite

The spin orientation in synthetic hematite-ilmenite samples and in a sample of natural hematite was studied from room temperature to above the antiferromagnetic-paramagnetic phase transition (the Néel temperature; $\textit{T}$$_{N}$ ≈ 600 − 950 K ) by neutron powder diffraction and at room temperature by Mö ssbauer spectroscopy. The usually assumed magnetic structure of hematite within this temperature range is antiferromagnetic with the spins confined to the basal plane of the hexagonal structure , however, an out-of-plane spin component is allowed by the symmetry of the system and has been observed in recent studies of synthetic hematite samples. We find the spins in the antifer romagnetic sublattices to be rotated out of the basal plane by an angle between 11 (2)° and 22.7(5)° in both synthetic hematite-ilmenite samples and in the natural hematite sample. The spin angle remains tilted out of the basal plane in the entire temperature range below the Néel temperature and does not depend systematically on Ti-content. The results indicate that the out-of-plane spin component is an intrinsic feature of hematite itself, with an origin not yet fully understood, but consistent with group theory. This represents a major shift in understanding of one of the two main mineral systems responsible for rock magnetism.This work was supported by the Danish Agency for Science, Technology and Innovation through DanScatt. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) ERC grant agreement 320750 and NERC Grant NE/D522203/1

The Architecture of a Root Zone of a Large Magmatic Conduit System From High Resolution Magnetic, Gravity and Petrophysical Data: The Reinfjord Ultramafic Complex

The Seiland Igneous Province (SIP) is a large province of mafic and ultramafic (UM) complexes interpreted to be relics of a giant plumbing system feeding the Ediacaran Central Iapetus Magmatic Province. The Reinfjord Ultramafic Complex (RUC) is one of the four major ultramafic complexes of the SIP. The RUC has a younger dunite core surrounded by wehrlite and lherzolite embedded in country rocks consisting of layered gabbros with sub-horizontal layering and metamorphosed sedimentary rocks. Here, we develop a 3D subsurface model for the RUC using high-resolution magnetic and gravity data and extensive petrophysical measurements from oriented surface samples and drill core samples. Our model indicates that the RUC narrows in depth, extending a minimum of 1.4 km below sea level, and plunges eastwards below the country rock. This model allows us to decipher the lithologic heterogeneities, and the depth and lateral extent of ultramafic rocks, which we interpret in the context of the geologic history of the area. The RUC is spatially separated from other UM complexes of the SIP and the result of this study indicates a smaller depth extent. Combining these findings with the previously reported distribution of the SIP rocks based on the regional gravity data, we propose that the uplift of the crustal block hosting the RUC is larger than for ultramafic complexes in the northwestern part of the SIP

Excavations at Gournia, 2010-2012

This article presents previous research at Gournia, the overall goals of our project, a new plan of the settlement, and our 2010-2012 excavations in eight areas: the Pit House, the Northwest Area, the North Cemetery, North Trench, the Northeast Area, House Aa, several rooms in the palace, and House He. Analytical sections discuss the textual evidence; the painted plasters; and the botanical remains. Our excavations indicate that Gournia was first settled in the Final Neolithic period and grew into an industrial town by the Protopalatial period. Following a Middle Minoan II destruction, the town was reorganized in Middle Minoan IIIA to include the palace, which in Late Minoan IB employed Linear A

Organizational commitment and turnover intention among rural nurses in the Philippines: Implications for nursing management

Objectives: The unrelenting migration trend of Filipino nurses to other countries has threatened the quality of patient care services in the country. This study explored the extent of nurses' organizational commitment and turnover intention in the Philippines. Furthermore, predictors of nurses’ organizational commitment and turnover intention were identified. Methods: A cross-sectional research design was adopted for this study. Two hundred nurses from nine rural hospitals in the Central Philippines were asked to participate in the study and 166 nurses responded (an 83% response rate). Two standardized instruments were used: the Organizational Commitment Questionnaire and the Six-item Turnover Intention Inventory Scale. Results: Findings revealed that Philippine nurses were moderately committed (3.13 ± 0.24) to and were undecided (2.42 ± 0.67) whether or not to leave their organization. Nurses' age (P = 0.006), gender, (t = -2.25, P = 0.026), education (t = 2.38, P < 0.001), rank(t = 4.38, P < 0.001), and work experience (t = 2.18, P = 0.031) correlated significantly with organizational commitment, while nurses’ age (P = 0.028) and education (t = 1.99, P = 0.048) correlated significantly with turnover intention. An inverse relationship was identified between the organizational commitment and turnover intention (r = −0.22, P = 0.005). Conclusion: The findings of this study highlight the need for formulation and implementation of interventions to promote life-long commitment in nurses and to reduce turnover rates. Keywords: Hospitals, Rural, Nurses, Organizational commitment, Philippines, Turnover intentio

Magnetic exchange bias of more than 1 Tesla in a natural mineral intergrowth

Magnetic exchange bias is a phenomenon whereby the hysteresis loop of a 'soft' magnetic phase is shifted by an amount HE along the applied field axis owing to its interaction with a 'hard' magnetic phase. Since the discovery of exchange bias fifty years ago1, the development of a general theory has been hampered by the uncertain nature of the interfaces between the hard and soft phases, commonly between an antiferromagnetic phase and a ferro- or ferrimagnetic phase. Exchange bias continues to be the subject of investigation because of its technological applications and because it is now possible to manipulate magnetic materials at the nanoscale2, 3, 4, 5, 6. Here we present the first documented example of exchange bias of significant magnitude (>1 T) in a natural mineral. We demonstrate that exchange bias in this system is due to the interaction between coherently intergrown magnetic phases formed through a natural process of phase separation during slow cooling over millions of years. Transmission electron microscopy studies show that these intergrowths have a known crystallographic orientation with a known crystallographic structure and that the interfaces are coherent

Rock magnetic and paleomagnetic investigations using a giant magneto resistance-based scanning magnetometer

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