Income investors who seek stability should start and end their searches with Dividend Aristocrats. To qualify, a company has to have increased its dividend for at least 25 years in a row, which is an achievement that few businesses can replicate.

So what Dividend Aristocrats are great buys right now? We asked a team of Fools that very question. They picked 3M (MMM 0.41%)Medtronic (MDT 0.89%), and TransCanada (TRP 0.33%). Read on to find out why.

Clock with dollar bills around it.

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A dividend with serious staying power

Anders Bylund (3M): Your average, run-of-the-mill Dividend Aristocrat has raised its annual payouts for at least 25 years running. There's nothing "average" about genre-busting technology company 3M, which has boosted its dividends without fail in each of the last 58 years.

3M's latest dividend check was cut three weeks ago, amounting to $1.175 per share. It was a 6% increase from the $1.11 payment per share of the previous four payouts, working out to a solid 2.5% yield. The dividend policy has consumed just 51% of 3M's trailing free cash flows, leaving lots of room for further increases.

A quick run through the Gordon growth model shows that the stock is priced for long-term annual share-price gains of roughly 12%. On top of that, management is committed to returning cash to shareholders in a big way. Beyond the 58-year streak of dividend increases, the payouts have been flowing without interruption for an even 100 years.

This dividend is going places, in all the right directions.

Clearly visible dividend growth on the horizon

Matt DiLallo (TransCanada): Canadian energy infrastructure giant TransCanada might not fit the exact definition of a Dividend Aristocrat just yet. However, it has increased its payout for the past 17 years. Further, those haven't been trivial raises to keep the streak alive, since it has delivered 7% compound annual dividend growth over that time frame.

Meanwhile, there's plenty more still left in the tank. The company is currently working through a $23 billion Canadian dollar ($17.3 billion U.S.) project backlog, which it expects will supply it with the cash flow to increase the payout by an 8% to 10% compound annual rate through 2020.

There's a high probability that TransCanada can achieve those expectations, because more than 95% of its cash flow comes from fee-based and regulated sources, and it pays out less than half of that in dividends, which leaves it with plenty of excess to help finance growth projects. On top of that, the company maintains a top-tier credit rating, giving it open access to inexpensive capital to fund the balance of its capital expenditure (capex) needs.

In addition to the clearly visible near-term growth from projects already in development, the company has another $45 billion Canadian dollars of longer-term projects on the way. These include the recently approved Keystone XL pipeline and some major gas pipeline projects for future liquefied natural gas (LNG) facilities in western Canada. As a result, there's growing probability that TransCanada can keep its dividend growth streak alive for quite some time, making this a future dividend aristocrat that investors will want to consider buying this month.

The medical-device kingpin

Brian Feroldi (Medtronic): With the major indexes trading near all-time highs, there are not a lot of bargains floating around. In times like this, I think investors are best served by tripling down on quality, even if they have to pay a slight premium. If you agree, then I'd recommend getting to know Medtronic.

Medtronic is a diversified medical-device maker with a long history of success. This company has been an innovation and acquisition machine over the last few decades, and it currently breaks up its business into four main categories -- diabetes, cardiac and vascular, minimally invasive, and restorative therapies.

The company holds a strong competitive position in each of these segments, allowing it to crank out reliable cash flow year after year. In turn, the company uses its huge financial might to make tuck-in acquisitions, buy back stock, and raise its dividend. Given that the company has increased its dividend for 39 years in a row, it's clear that this company has created a winning business model.

Looking ahead, Medtronic looks well positioned for revenue and profit growth. That's because the world's population is aging and growing wealthier, which should drive demand for high-quality healthcare. That plays right into Medtronic's hands, since it derives about 44% of its revenue from overseas markets.

Mix in small price increases on its current prices and a steady rollout of new innovation, and I think this Dividend Aristocrat is a fine large-cap stock to consider buying today.