Home CINS
Serpintinite - Simone Pujatti

Neutrons Take Geology to New Scales

CINS Scattering Spotlight: Simone Pujatti

Source: Mitchell DiPasquale 
Contact: webmaster@cins.ca
Image: (Left) Serpentinite Rock (Right) 3D Rendering of porous network in a serpentinite (scale = 500 nm).

We’re all familiar with how rainwater flows across the ground into streams and rivers after a heavy rainfall. But what happens to the water that soaks deep into the soil and rocks?

The reactions between water and rock control the chemical evolution of the Earth. Water seeping through the Earth’s crust changes the rock and influences global-scale processes such as plate tectonics. One of the most important of these reactions is serpentinization, which occurs when rocks from the Earth’s mantle, upwelling at mid-ocean ridge, interact with seawater. The resulting green and scaly serpentinites may have been the key to the origin of life.

Simone Pujatti, University of Calgary
PhD Student, Simone Pujatti, University of Calgary

Vast regions of oceanic mantle rock have almost completely been transformed into serpentinite, releasing hydrogen and methane that can be used as nutrients by early-Earth microorganisms. The process of how water has been able to infiltrate deep into these highly impermeable rocks is still very much a mystery.

Conceptually, serpentinization deep into the mantle rock is fueled by a constant supply of water and solutes that creep through the porous network formed by the spaces between the solid particles of rock. In reality, theory predicts that the serpentinite formed in the reaction should clog the pores of the rock, sealing off the supply of reactants, and stopping the transformation. Unfortunately, to limitations of classic geological characterization techniques, researchers have yet to study the extremely small pore structure of serpentinites – ranging from tens to hundreds of nanometers.

Simone Pujatti, a PhD student at the University of Calgary, is employing a modern solution to research the feedbacks between serpentinization and porosity to explain how this reaction has taken over the Earth’s mantle.

Using a combination of small and ultra-small angle neutron scattering, Simone will capture and quantify the whole distribution of pore sizes in various mantle rocks drilled from under the Atlantic Ocean. Each sample is meticulously chosen to reveal the evolution of the pore network as serpentinization progresses.

“The evidence generated will elucidate the relationship between serpentinization extent, volume increase and changes in porosity. This will impact our understanding of systems both at the molecular level, as the pores can be inhabited by microorganisms, and at the regional scale since porosity changes drive serpentinization reactions through the oceanic crust.”

Simone Pujatti, University of Calgary

Neutrons provide a non-destructive technique to study the nano-scale porosity of materials, including rocks, under the high temperatures and pressures in which they naturally form. The broad microstructural range quantifiable by combining multiple neutron scattering techniques offers a unique tool to modern geoscientists, and Simone hopes it will provide the evidence necessary to resolve a century-old issue about solid volume increase during serpentinization.

CINS Scattering Spotlight aims to raise awareness for the world-class neutron research being conducted by students across Canada. We encourage you to share your research stories by contacting tharroun@brocku.ca

Thank you!

63 Canadian researchers responded to our survey of how they are able to meet their research needs with neutron beams. We’re tabulating the responses to see how things are in the two years since the closure of the CNBC.

Nickel hydride catalyst

Neutrons Uncover Clues for Better Catalysts

CINS Scattering Spotlight: Dr. Manar Shoshani

Source: Mitchell DiPasquale 
Contact: webmaster@cins.ca
Image: A) 1.5 mm3 single crystalline nickel-hydride for neutron diffraction. B) Neutron diffraction-solved structure. C) ChemDraw depiction of cluster.

From cleaning the toxic exhausts of your car’s engine, to the green promise of plastic upcycling, to the biological processes that keep you alive – achieving efficient results in chemical changes is driven by catalysts.

The ability of nature to selectively carry out multi-electron chemistry under ambient conditions has long inspired catalytic design.  Innovation in synthetic catalysts can unlock novel reactions and allow cheaper, cleaner, and more efficient pathways to new and improved materials.

Dr. Manar Shoshani
Dr. Manar Shoshani

Former UWindsor PhD student Manar Shoshani took inspiration from multi-metallic enzyme active sites to try to emulate this robust reactivity in homogenous transition metal clusters. Under the guidance of Dr. Samuel A. Johnson, Manar sought to understand how the multi-metal centres interact to promote catalysis, with hopes of providing a trajectory toward intelligent design of better catalysts. 

With molecular nickel-hydride clusters, Manar observed remarkable activations of C–C, C–O, and C–S bonds as well as catalytic activation of C–H bonds, all of which proceeded rapidly at room temperature. Knowledge on the solid-state structure of the complex is vital to decipher the mechanistic intricacies that drive these processes.

“Determining the unambiguous solid-state structure of these complexes is imperative to understanding both the properties of the cluster, as well as the potential for these clusters to serve as catalysts.”

– Dr. Manar Shoshani, Caltech Post-Doctoral Fellow

Synthetic chemists naturally lean on X-ray crystallography for structural information; however, light atoms (particularly hydrogen), coordinated in these complexes are largely invisible to studies by X-ray. For Manar, neutron diffraction served as the ideal complement to be able to pinpoint the hydride locations in the cluster, and to clue into the details of metal-metal cooperativity.

A step further, as neutrons interact with hydrogen and deuterium differently, the experiment also provided insight into the catalytic hydrogen-deuterium exchange activity of the clusters. Neutrons offer an exceptional means to uncover the finesse of transition metal hydride catalysts. A deeper understanding of metal-metal cooperativity can help usher in a new wave of efficiency with rationally designed catalysts.

After completing his PhD, Dr. Shoshani continues to contribute to catalyst innovation as a post-doctoral fellow at the California Institute of Technology.

For more information on this work, the published manuscript can be found at Shoshani, Manar M., Robert Beck, Xiaoping Wang, Matthew J. McLaughlin, and Samuel A. Johnson. Inorganic Chemistry 57, 5 (2017): 2438-2446.

CINS Scattering Spotlight aims to raise awareness for the world-class neutron research being conducted by students across Canada. We encourage you to share your research stories by contacting tharroun@brocku.ca

Atomic structure of a mineral perovskite

Neutrons Point to Next-Generation Computer Memory Materials

CINS Scattering Spotlight: Dr Dalini Maharaj, TRIUMF

Source: Mitchell DiPasquale 
Contact: webmaster@cins.ca
Image: Crystal structure of a mineral perovskite. (Wikimedia CC-BY-SA 3.0)

As our music and movie libraries grow and the number of apps we use multiplies, everyone wants faster devices with larger data storage. Former McMaster PhD student Dalini Maharaj studies novel magnetic materials that could very well usher in the next generation data storage technology, particularly in disk drive read-and-write heads. In principle, one could reduce the size of the data storage unit if the data density could be increased in these hard-disks. New kinds of quantum materials are needed to fulfil this promise.

“Of course, before these new technologies can be realized, much work needs to be performed to understand the properties of the candidate materials.” – Dr. Dalini Maharaj, TRIUMF Post-Doctoral Fellow

Dr. Maharaj’s PhD work involved the study of the quantum magnetic properties of crystalline materials via X-ray and neutron scattering methods. Working in Prof. Bruce D. Gaulin’s group at McMaster University, she synthesized novel materials which are theoretically predicted to exhibit exotic magnetic properties. This class of materials, referred to as the double perovskites, have phases that involve `frustrated` magnetic interactions, whereby the magnetic dipoles of the atoms cannot arrange themselves into a low energy configurations. Members of this family are widely studied as they are shown to exhibit a wide variety of unique properties including superconductivity, ferroelectricity and colossal magnetoresistance, the latter being a prime candidate for increasing the data density of hard drives. In particular, Dalini’s doctoral work involved the study of non-trivial arrangements of magnetic atoms in d-electron double perovskites which are driven by magnetic interactions that can only be theoretically analysed with advanced quantum mechanics.

Dr. Dalini Maharaj

Neutrons are an indispensable probe of the magnetic properties of materials as they are electrically neutral and they possess the property of spin. These properties enable neutrons to deeply penetrate matter and interact directly with the magnetic degrees of freedom in solid state materials. The energy spectra which are obtained from neutron scattering experiments provide important clues for identifying the magnetic ground state of the materials being investigated.

Most recently, Dalini’s neutron scattering studies on the cubic double perovskite materials led to discover the first instance of octupolar order in d-electron magnets. This discovery highlights the relevance of multipolar interactions in heavy d-electron magnets and consequently, the potential for the realization of novel materials for future applications.

Upon completing her PhD, Dalini remained in the field of neutron sciences and is currently completing a postdoctoral fellowship at TRIUMF, through the University of Windsor, studying potential targets and moderators for a future compact accelerator neutron source.

CINS Scattering Spotlight aims to raise awareness for the world-class neutron research being conducted by students across Canada. We encourage you to share your research stories by contacting tharroun@brocku.ca

“Neutrons Canada” meeting report available

On 2020 January 29, the Vice Presidents of Research or their designates from 16 Canadian universities met in Ottawa to discuss a proposed new pan-Canadian, university-led framework to manage Canada’s infrastructure, international partnerships, projects, and programs for materials research with neutron beams.

CINS is pleased to announce that a 21-page, fulsome report of the meeting is now available for download here:
https://fedorukcentre.ca/documents/resources/cni/neutrons-canada-roundtable-2020-jan-29—full-report.pdf

The report builds on the consensus of the meeting that Canada should maintain its leadership role in materials research with neutron beams. It has an extensive list of policy resources, and discussion of example strategic roadmaps from Europe and elsewhere.

Europe leans in to help establish Neutrons Canada

On January 29, Fifteen senior executives of Canada’s research universities met in Ottawa with Dr Mona Nemer, Canada’s Chief Science Advisor, and several of our European colleagues to discuss how to establish a new cross-Canadian university-led organization to manage Canada’s infrastructure for materials research with neutron beams.

BrightnESS², the European Union-funded project within the European Commission’s Horizon 2020 Research and Innovation programme, wrote a report of the meeting, which included John Womersley, ESS Director General, and ILL Director Helmut Schober.

70 Years of Neutron Beams for Materials Research: The CNBC Releases Its Final Activity Report

With the release of its final activity report, the Canadian Neutron Beam Centre (CNBC) celebrates Canada’s leadership in the use of neutron beams for materials research for over 70 years.

“Our leadership began with the startup of the NRX reactor at Chalk River Laboratories in 1947,” says John Root, Director of the CNBC. “It spanned from the pioneering days of developing neutron scattering techniques through to the global recognition of neutron beams as an invaluable tool for the study of materials.”

The importance of these advancements was marked by the 1994 Nobel Prize in Physics, as well as by the proliferation of neutron beam facilities around the world.

“Today, we are proud to have grown a strong Canadian community of neutron beam users who have engaged with us to maximize value from our beamlines until the very last moment of the NRU reactor’s operating life in March 2018,” continues Root.

Since the closure of the NRU reactor, the CNBC has been in a decommissioning phase.

“As we look forward to the future by securing access to neutron beams from alternate facilities, now is an appropriate time to pause and reflect on Canada’s strong record of performance and impact, as presented in this report,” adds Thad Harroun, President of the Canadian Institute for Neutron Scattering.   

Read the 2019 CNBC Activity Report